MXPA96003134A - Method for removing sulfone present in hydrocarbon - Google Patents

Abstract

Disclosed is a process for removing sulfone from a liquid hydrocarbon containing a concentration of sulfone by mixing a liquid acid therewith and thereafter separating the resulting admixture into an acid phase and a hydrocarbon phase. The hydrocarbon phase has a concentration of sulfone less than such concentration in the liquid hydrocarbon.

Description

A METHOD FOR ELIMINATING OR REMOVING SULPHONE FROM A LIQUID HYDROCARBON CURRENT FIELD OF THE INVENTION The present invention relates to the process of an alkylation reactor effluent produced by the catalytic alkylation of olefins with isoparaffins using a hydrazide catalyst in a sulfone diluent. More particularly, the invention relates to the removal of sulfone from an effluent of the alkylation reactor.

BACKGROUND OF THE INVENTION A newly discovered alkylation catalyst mixture recently discovered contains a hydrazide component in a sulfone diluent. While the components of the alkylation catalyst mixture are substantially immiscible with hydrocarbons, particularly an alkylate product, the sulfone component is still slightly soluble in hydrocarbon. Accordingly, there may be a small concentration of sulfone in an alkylate product produced by the catalytic alkylation of olefins by isoparaffins REF: 22775 that use as a catalyst a hydrazide in a sulfone diluent. The concentration of sulfone in the alkylate product may vary upwards from about 4000 parts per million by weight (ppmp). A high concentration of sulfone in the alkylate product is undesirable because of the use of alkylate as a material that mixes gasoline from the engine. The sulfone concentration in the alkylate should be less than about 100 ppmp.

BRIEF DESCRIPTION OF THE INVENTION Indeed, it is an object of this invention to provide a method for removing sulfone from an alkylation reactor effluent having an undesirably high concentration of sulfone so as to provide an alkylate product with a low concentration of sulfolane. Accordingly, the inventive method isprovided for the removal of sulfone from a liquid hydrocarbon stream having a sulfone concentration in the range of about 150 ppm to approximately 4000 ppm. This method includes mixing the liquid hydrocarbon stream with liquid hydrogen fluoride into a mixing zone to form a mixture of hydrogen fluoride and the liquid hydrocarbon stream. The mixture is passed to a phase separation zone where it is separated into at least two liquid phases including a hydrocarbon phase and an acid phase. The hydrocarbon phase has a sulfone concentration that is lower than the sulfone concentration in the liquid hydrocarbon stream, and the acid phase includes a sulfone concentration.

BRIEF DESCRIPTION OF THE DRAWING In the attached drawing: Figure 1 is a schematic representation of the process which is one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION The new method described herein is provided for the removal of contaminating sulfone concentration levels, contained in an alkylation reaction product known as alkylate. The alkylation reaction product, or alkylate, may have a concentration of the sulfone used as a diluent for a hydrazide component to form a novel alkylation catalyst mixture. In general, the sulfone can be present in the alkylate up to its maximum level of solubility in it. This concentration of sulfone, however, can be especially undesirable when the alkylate is used as a mixing component of a final gasoline product. Accordingly, it is necessary to remove a portion, preferably, a significant portion, of the concentration of sulfone contained in an alkylate product so as to provide a sulfone concentration in the alkylate that is less than about 100 ppmpm. The alkylate product of the present invention is a hydrocarbon produced by an alkylation process that involves the catalytic alkylation of olefins with isoparaffins. In general, the alkylation processes contemplated in the present invention are those liquid phase processes wherein mono-olefin hydrocarbons such as propylene, butylenes, pentylenes, hexylenes, heptylenes, octylenes and the like are alkylated by hydrocarbons of isoparaffin such as isobutane, isopentane, isohexane, isohentane, isooctane and the like for the production of high-octane alkylate hydrocarbons that do not boil or boil in the range of gasoline and which are suitable for use in the fuel substance of the gasoline engine . Preferably, the isobutane is selected as the fine isoparaffin reagent and the olefin rectifier is selected from propylene, butylenes, pentylenes and mixtures thereof for the production of an alkylate hydrocarbon product comprising a larger portion. of highly branched, high octane aliphatic hydrocarbons having at least seven carbon atoms and less than ten carbon atoms. In order to selectively improve the alkylation reaction towards the production of the highly branched, desirable aliphatic hydrocarbons having seven or more carbon atoms, a substantial stoichiometric excess of isopara fine hydrocarbon is desirable in the reaction zone. The proportions or molar ratios of hydrocarbon from isoparaffin to olefin hydrocarbon from about 2: 1 to about 25: 1 are contemplated in the pre-sent invention. Preferably, the molar ratio of isoparaffin to olefin could vary from about 5 to about; and, more preferably, it would vary from 8 to 15. It is emphasized, however, that the ranges referred to above for the molar ratio or ratio of isoparaffin to olefin are those that have been found to be commercially practical working or operational ranges; but, in general, the higher the ratio or ratio of isoparaffin to olefin in an alkylation reaction, the better the resulting alkylate quality will be. The reactive isoparaffin and olefin hydrocarbons normally used in commercial alkylation processes are derived from refinery process streams and usually contain small amounts of impurities such as normal butane, propane, ethane and the like. Such impurities are undesirable in high concentrations because they dilute reactants in the reaction zone, therefore, they decrease the available reactor capacity for the desired reagents and interfere with the good contact of isoparaffin with olefin reagents. Additionally, in continuous alkylation processes wherein the excess isoparaffin hydrocarbon is recovered from an alkylation reaction effluent and recirculated to make contact with the hydrocarbon, of additional olefin, such normal, non-reactive paraffin impurities tend to accumulate in the alkylation system. Accordingly, the process charge streams and / or recirculation streams containing substantial amounts of normal paraffin impurities are usually fractionated to remove such impurities and maintain their concentration at a low level, preferably less than approximately 5 times. hundred in volume, in the process of alkylation. The alkylation reaction temperatures within the consideration of the present invention are in the range of about -17.78 ° C (0 ° F) to about 65.55 ° C (150 ° F). Lower temperatures favor the alkylation reaction of isoparaffin with olefin over the competition of olefin side reactions such as polymerization. However, all reaction rates decrease with decreasing temperatures. The temperatures within the given range, and preferably in the range of approximately -1.11 ° C (30 ° F). at approximately 54.4 ° C (130 ° F), they provide good selectivity for the alkylation of isoparaffin with olefin at commercially attractive reaction rates. More preferably, however, the alkylation temperature could vary from about 10 ° C (50 ° F) to 43.3 ° C (110 ° F). The reaction pressures contemplated in the present invention may vary from pressures sufficient to maintain reactants in the liquid phase at about twenty-five (25) atmospheres of pressure.

The reactive hydrocarbons can be normally gaseous at alkylation reaction temperatures, therefore, the reaction pressures in the range of about 2.81 kg of gauge pressure per cm2 (40 pounds of gauge pressure per square inch) to 4218 kg / cm2 Gauge pressure (160 psi) is preferred. With all the reagents in the liquid phase, the increased pressure has no significant effect on the alkylation reaction. Contact times for hydrocarbon reagents in an alkylation reaction zone, in the presence of the alkylation catalyst of the present invention, should generally be sufficient to provide essentially complete conversion of the olefin reagent into the alkylation zone. Preferably, the contact time is in the range of about 0.05 minutes to about 60 minutes. In the alkylation process of the present invention, which employs the isoparaffin to olefin molar ratios in the range of about 2: 1 to about 25: 1, wherein the alkylation reaction mixture comprises about 40-90 percent by volume of the catalytic phase and approximately 60-10 volume percent of the hydrocarbon phase, and where the good olefin contact with isoparaffin is maintained in the reaction zone, the essentially complete conversion of olefin can be be obtained at olefin space velocities in the range from about 0.1 to about 200 volumes of olefin per hour per volume of catalyst (v / v / hr.). The optimal space velocities will depend on the type of isoparaffin and olefin reagents used, the particular compositions of the alkylation catalyst, and the alkylation reaction conditions. Accordingly, the preferred contact times are sufficient to provide an olefin space velocity in the range of about 0.1 to about 200 (v / v / hr) and allow essentially complete conversion of the olefin reagent into the alkylation zone. The alkylation process can be performed either as a continuous or discontinuous type of operation although it is preferred for economic reasons to carry out the process continuously. It has generally been established that in alkylation processes, the most intimate is the contact between the raw material and the catalyst, the best the quality of the alkylation product obtained. With this in mind, the present process, when operated as a discontinuous operation, is characterized by the use of vigorous mechanical agitation or trepidation of the reactants and catalyst. In continuous operations, in one embodiment, the reactants can be maintained at pressures and temperatures sufficient to keep them substantially in the liquid phase and then continuously forced through dispersion devices in the reaction zone. The dispersion devices may be spouts, injectors, shutters or mandrels, and the like. The reagents are subsequently mixed with the catalyst by conventional mixing or mixing means such as mechanical stirrers or turbulence of the flow system. After a sufficient time, the product can then be continuously separated from the catalyst and withdrawn from the reaction system while the partially used catalyst is recirculated to the reactor. If desired, a portion of the catalyst can be regenerated or reactivated continuously by any suitable treatment and returned to the alkylation reactor. The alkylation catalyst used in the alkylation reaction may be a novel composition suitable for use as an alkylation catalyst which may comprise, consist of, or consist essentially of a hydrazide component and a sulfone component. The hydrazide component of the catalyst composition or catalyst mixture can be selected from the group of compounds consisting of hydrogen fluoride (HF)., hydrogen chloride (HCl), hydrogen bromide (HBr), and mixtures of two or more thereof. The preferred hydrazide component, however, is hydrogen fluoride, which can be used in the catalyst composition in the anhydrous form, but, generally, the hydrogen fluoride component used can have a small amount of water. The amount of water present in the mixture of hydrogen fluoride and sulfolane can in no case be more than about 30 weight percent of the total weight of the hydrogen fluoride component, which includes water, and preferably, the amount of water present in the hydrogen fluoride component is less than about 10 weight percent. Most preferably, the amount of water present in the hydrogen fluoride component is less than 5 weight percent. When referring herein to the hydrazide component, or more specifically to the hydrogen fluoride component, of the catalytic composition of the invention, it should be understood that these terms mean either the hydrazide component as an anhydrous mixture or a mixture including water. References here to percent by weight of water contained in the hydric component means the ratio or proportion of the weight of the water to the sum of the weight of the water and hydroid multiplied by a factor of 100 to establish the ratio or proportion by weight in terms of percent. The sulfones suitable for use in this invention are the sulfones of the general formula R-S02-R ' wherein R and R 'are substituents of aryl or monovalent hydrocarbon alkyl, each containing from 1 to 8 carbon atoms. Examples of such substituents include dimethylsulfone, di n-propylsulfone, diphenylsulfone, ethyl ethylsulfone and the alicyclic sulfones wherein the SO group is linked to a hydrocarbon ring. In such a case, R and R 'are uninterrupted formers of a divalent moiety of branched or unbranched hydrocarbon, preferably containing from 3 to 12 carbon atoms. Among the latter, tetramethylene sulfone or sulfolane, 3-methylsulfolane and 2,4-dimethylsulfolane are more particularly suitable since they offer the advantage of being liquid under operating conditions of the process of interest herein. These sulfones may also have substituents, particularly one or more halogen atoms, such as, for example, chloroethylethylsulfone. These sulfones can be advantageously used in the form of mixtures. The alkylation reactor effluent contains an alkylate product produced by the alkylation process, which utilizes a sulfone and hydrazide catalyst under normal or standard temperature and pressure conditions, and generally could be a liquid hydrocarbon having a concentration of sulfone in the range of approximately 150 ppmp to approximately 4000 ppmp. More specifically, however, the sulfone concentration in the reactor effluent gives alkylation may be in the range of about 150 ppm to approximately 3000 ppm, and, more specifically, the concentration is in the range of 200 to 200 ppm. 2500 ppmp. It is desirable to remove a portion, preferably a substantial portion, of the sulfone contained in the effluent of the alkylation reactor therefrom. This is done by mixing with the effluent of the alkylation reactor a liquid acid comprising hydrogen fluoride but preferably containing a predominant amount of hydrogen fluoride to form a mixture of the alkylation reactor effluent and the liquid acid. The mixture is brought to a separation zone where the mixture is allowed to separate into at least two substantially immiscible liquid phases one of which is a hydrocarbon or hydrocarbon phase and the other is an acid phase. The hydrocarbon phase can therefore have a sulfone concentration that is lower than the concentration of sulfo-na in the effluent of the alkylation reactor. The liquid acid comprises hydrogen fluoride which generally has a concentration of hydrogen fluoride exceeding about 80 weight percent. Preferably, the liquid acid would have a concentration of hydrogen fluoride of at least 85 percent by weight and, more preferably, the concentration is at least 90 percent by weight. The concentration of hydrogen fluoride in the liquid acid can have a major impact on the operation of the method for removing sulfone from a liquid hydrocarbon containing such sulfone. The higher the concentration of hydrogen fluoride, and therefore the purity of the liquid acid, the better the extraction efficiency of the liquid acid will be. The acid phase may have hydrogen fluoride present at the same concentration ranges as those of the liquid acid but also have a sulfone concentration which has been removed from the effluent of the alkylation reactor. While the concentration of sulfone in the acid phase is highly dependent on the concentration of sulfone in the effluent of the alkylation reactor, it may generally be in the range of more than about 15 weight percent but, preferably, in the range from about 0.1 weight percent to about 7.5 weight percent. More preferably, the sulfone concentration in the acid phase is in the range of 0.1 weight percent to 5 weight percent. The inventive method can be provided for the removal of a significant portion of the sulfone concentration in the effluent from the alkylation reactor. Particularly, at least about 40 weight percent of the sulfone concentration in the effluent of the alkylation reactor is removed therefrom. Preferably, however, it is desirable to remove at least about 50 percent by weight of sulfone from the effluent of the alkylation reactor; and, more preferably, at least 60 weight percent of the sulfone should be removed from the effluent of the alkylation reactor. The fractional amount of sulfone removed from the effluent of the alkylation reactor containing a sulfone concentration, the hydrocarbon phase mentioned above, having a sulfone concentration lower than the sulfone concentration in the effluent of the alkylation reactor, is omitted. / must have a sulphonate balance of less than apimately 100 ppmp. Preferably, the concentration of sulfone in the hydrocarbon or hydrocarbon phase is less than about 50 ppmp; and, more preferably, the concentration is less than 25 ppmp. The mixing step can be effected by any means or method which suitably ides for the mixing or contacting of the liquid acid with the effluent of the alkylation reactor to form a mixture. Subsequent separation of the mixture in at least two liquid phases can be carried out by any means or method which suitably ides its separation in the hydrocarbon phase and the acid phase. When mixing or contacting the liquid acid with the alkylate, any apparatus suitable for iding intimate mixing or contact can be used such as flow or linear mixers and mechanically agitated containers. Examples of linear or flow type mixers include eductors, mixers by injection, injectors, orifices or diaphragms, mixing injectors, valves, pumps, line mixers or stirred feed, packaging tubes, pipes and the like. Mechanically agitated containers include such devices as containers equipped with injectors or ellers used to achieve mixing and dispersion. It is generally desirable to use a continuous ess according to which the liquid acid is mixed continuously with the alkylate followed by a phase separation of the resulting hydrocarbon phase and the acid phase by any means or method which is suitably ided for separating the at least two immiscible liquid phases including the hydrocarbon phase and the acid phase. In the continuous ess, it is common for the passage of the mixture or contacting to be effected separately, and by a separate apparatus, from that of the separation step. The flow or line mixers ide them with suitable means to mix in a continuous ess. The steps of mixing and phase separation can also be conducted in a discontinuous manner usually in a single vessel defining both a mixing zone and a phase separation zone. The mechanically agitated containers can be used as apparatuses that allow the discontinuous mixing of the effluent of the alkylation reactor and the liquid acid, and separate the resulting acid and the hydrocarbon phases. The preferred mixing means for mixing the liquid acid and the effluent of the alkylation reactor to thereby form a mixture is an eductor used to extract the acid phase from the separation zone. The acid phase is, therefore, used as the liquid acid. As for the separation of the immiscible liquid phases, a container, which defines a phase separation zone, can be used apriately; it is ided, it has the er volume to allow the separation of the immiscible fluids by gravity or any other apriate means. Other mechanical devices, such as, for example, centrifugal machines, can be used to effect the separation of the immiscible phases. Any amount of liquid acid relative to the amount of the effluent from the alkylation reactor / can be used in the ess ided that the amount of liquid acid mixed with the effluent from the alkylation reactor is sufficient to cause the subsequent formation of at least two phases. -quides, immiscible, which include a hydrocarbon phase having a sulfone concentration lower than the sulfone concentration in the alkylation reactor effluent, and an acid phase having a sulfone concentration resulting from the removal of sulfone from the effluent of the alkylation reactor. In the mixing step, a sufficient quantity of liquid acid is to be mixed with the effluent of the alkylation reactor, which contains sulphone, to subsequently provide a hydrocarbon phase containing a reduced concentration of sulfone. It is desirable to mix an amount of liquid acid with the effluent from the alkylation reactor such that the ratio or volumetric ratio of the liquid acid to the effluent of the alkylation reactor exceeds about 0.25: 1 to thereby form the mixture. In general, the volumetric ratio from the liquid acid to the effluent of the alkylation reactor, it may be in the range of about 0.5: 1 to about 2: 1. Preferably, the volumetric ratio of liquid acid to effluent from the alkylation reactor can be in the range of about 0.75: 1 to about 1.5: 1.; and, more preferably, it is between 0.9: 1 to 1.1: 1. The process conditions under which both mixing and separation are performed, include temperatures in the range of about -17.77 ° C (0 ° F) to about 121 ° C (250 ° F), with 4.44 ° C ( 40 ° F) at 71 ° C (160 ° F) which are preferred. Process pressures include those within the range of approximately 0.5 atmospheres absolute pressure to approximately 30 atmospheres of absolute pressure, with 0.95 atmospheres of absolute pressure at 25 atmospheres of absolute pressure that are preferred. Referring now to Figure 1, the schematically illustrated alkylation unit includes the HF 10 alkylation system, recontactor 12, and separation system 14 and other relevant equipment. The alkylation system of HF 10 includes the alkylation reactor 20, the phase separator, or settler, 22, the acid storage vessel 23, and the acid cooler 26. The olefin feed, the isoparaffin feed and the recirculated isoparaffin, are charged to the alkylation system 10 through the conduits 13, 15 and 16, respectively, where they enter the recirculation-feed mixer 18 prior to being charged to the alkylation reactor 20. The feed of isoparaffin-olefin is contacted with an acid catalyst, which contains hydrogen fluoride and a sulfone, in the reaction zone defined by the alkylation reactor 20. From the alkylation reactor 20, the effluent, which may contain the hydrocarbon (alkylate) product, acid catalyst, and other hydrocarbons, is introduced to the settler 22 wherein an alkylation reactor effluent, containing alkylate and other hydrocarbons, rocarburos, is separated from the acid catalyst. The acid catalyst is re-moved from the bottom of the settler 22 and flows through the line 24 to the heat exchanger 26 where it is cooled down and, optionally, separated. Part of the acid catalyst returns to the alkylation reactor 20, and the remainder can be transported through the conduit 28 by the pump 30, heated in the heat exchanger 32, and then introduced to a redistillation vessel of the acid 34. The bottoms of the Acid redistillation vessel 34 is removed through line 36 and treated to produce the acid soluble oil product (ASO). A regenerated acid catalyst is removed from the top of the redistillation vessel of the acid 34 and is introduced into the settler 22 through the conduit 37, which is in fluid flow communication with the redistillation vessel of the acid 34 and the settler 22. Additionally, the acid filler catalyst can be introduced from the acid reservoir 23 to the conduit 28 through the conduit 29 when needed. The effluent from the alkylation reactor is removed from the alkylation system 10 through the conduit 38 with the effluent from the alkylation reactor which is pumped through the conduit 38 and the valve 43 through the pump 42 to the eductor 44. The flow from the effluent of the alkylation reactor to the eductor 44, is controlled by the valve 43. The re-contactor 12 defines a phase separation zone wherein two immiscible phases including a hydrocarbon phase 46 and an acid phase 48, are separated by gravity. The acid phase is entrained to the eductor 44 via conduit 50 which provides fluid flow communication between the acid phase 48 and the eductor 44. The eductor 44 defines a mixing zone and provides for the mixing of the reactor effluent from the reactor. alkylation and the acid phase to form a mixture or additive. The mixture passes to the recontactor 12 through conduit 51. Within the recontactor 12, a phase separation occurs whereby the hydrocarbon phase is formed, which has a sulfone concentration lower than the sulfone concentration in the effluent of the alkylation reactor, and an acid phase is formed, which has a sulfone concentration. The conduit 52 is in fluid flow communication with both the recontactor 12 and the separation system 14. The separation system 14 that enters the recontactant effluent through the conduit 52 is separated into products, which include propane and other products. light, which are removed through line 60, and the alkylate and n-butane products, which are removed through line 62. The isoparaffin is removed from the alkylate, recirculated and returned to the alkylation system 10 through of the duct 16 where it is introduced to the feed-recirculation mixer 18. The hydrogen fluoride removed from the alkylate in the separation system 14, flows to the duct 38 through the conduit 59 and is returned as hydrogen fluoride to the recirculator 12 via the conduit 38. The flow in the conduit 38 is controlled by the valve 61.

Any accumulation of acid and alkylate impurities in the recontactor 12 is purged by removing the recontactor 12 through the conduit 50 to the conduit 55 and passing to the settler 22.

Example I (calculated) The information provided in Table 1 is an equilibrium or proportion of the calculated material that encircles or surrounds the mixer / eductor and the phase separator of the process to remove sulfolane from an effluent stream of the alkylation reactor to thereby give a hydrocarbon stream that it has a reduced concentration of sulfolane. This Example demonstrates the beneficial reduction in sulfolane concentration feasible by re-contacting the hydrogen fluoride with an alkylation reactor effluent having a sulfolane concentration to thereby remove at least a portion of the sulfolane. As can be seen from the information presented in Table 1, the concentration of sulfolane in the effluent of the alkylation reactor is about 257 ppmp. a percentage of removal or elimination of sulfolane of 92 percent is achieved. The accumulations of sulfolane in the acid phase to about 5 weight percent of the circulating acid. To control the accumulation of sulfolane, the purge rate must be adjusted. The recovery of sulfolane can be improved by increasing the manufacturing speed of hydrogen fluoride.

Table 1 Calculated Material Balance Around the Mixer-Recontactor System Example II This Example II provides the experimental procedure used to determine the ability of anhydrous HF to extract sulfolane from a hydrocarbon stream. The data shows that in all cases greater than 70 percent of sulfolane is removed from the hydrocarbon stream and, in many cases, the reduction is greater than 94 percent. A continuous reactor system was constructed and used for alkylation studies under continuous conditions. The reactor consists of a 2 'section of Monel 40 pipeline (308 mL) connected, through the 1/4"Monel pipe, to a Monel visual manometer (704 mL) used as a sedimentation vessel. The reactor was charged with the desired amount of acid (typically 300 grams) The reactor was wrapped with 1/2"(half inch) heating tape. The temperature of the acid phase is maintained at about 36-38 ° C by a temperature controller attached to the heating tape and verified by a thermocouple or thermocouple in the thermal source in the center of the reactor. The feed is mixed with isobutane (approximately 90 parts by weight) and light alkylate (approximately 10 parts by weight). Sulfolane is added to this base feed. The mixed feed was then pumped to the reactor (approximately 180 gr / hr) through an orifice to provide better dispersion of the hydrocarbon in the acid phase. After passing through the static acid phase, the hydrocarbon effluent is sampled at the top of the reactor. The hydrocarbon sample was diluted with pure isooctane and the mixture analyzed by sulfur. A sample of the feed was drawn at the same time and treated in the same way. Table II gives the results of the sulfolane removal of the hydrocarbon phase. vo Example III This Example III was carried out in the same manner as Example II, except that the acid phase was included of 95% by weight of HF and 5% by weight of sulfolane. Table III summarizes the results for these experiments and shows that the efficiency of the sulfolane removal is diminished by the accumulation of sulfolane in the acid phase of the recontactant.

Table III. Extraction of Sulfolane from Hydrocarbon by HF with 5% Sulfolane. Studies of Reference Vertical Conductor Sulfolano, ppmp 117 261 261 277 277 Temperature, ° C 37.9 36.8 38.3 37.4 38.9 Sulfolane effluent, ppmp 87 175 181 98 156 % Reduction 26 33 31 65 44 It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention. Having described the invention as above, the content of the following is claimed as property

Claims (10)

1. A method for removing sulfone from a liquid hydrocarbon stream having a sulfone concentration in the range of about 150 ppm to approximately 4000 ppm, the method is characterized in that it comprises: mixing within a mixing zone the stream of liquid hydrocarbon with a liquid acid comprising HF, to form a mixture of said liquid hydrocarbon stream and said liquid acid; and passing the mixture to a phase separation zone wherein said mixture is separated into at least two liquid phases including a hydrocarbon or hydrocarbon phase having a sulfone concentration lower than said concentration of sulfone in said liquid hydrocarbon stream, and an acid phase having a concentration of sulphone.

2. A method according to claim 1, characterized in that it further comprises removing the hydrocarbon or hydrocarbon phase from the separation zone.

3. A method according to claim 1 or 2, characterized in that it further comprises using said acid phase as the liquid acid.

4. A method according to claim 3, characterized in that the mixing zone is defined by an eductor used to remove the acid phase from the separation zone so that it uses the acid phase as a liquid acid mixed in the mixing or preparation zone. .

5. A method according to any of the preceding claims, characterized in that the ratio or weight proportion of the liquid acid to the liquid hydrocarbon stream is in the range of about 0.5: 1 to about 5: 1, preferably in approximate form 0.5: 1 to approximately 2: 1.

6. A method according to any of the preceding claims, characterized in that the concentration of HF in the liquid acid exceeds approximately 80 weight percent.

7. A method according to any of the preceding claims, characterized in that the sulfone is sulfolane.

8. A method according to any of the preceding claims, characterized in that at least 40 weight percent of the sulfone concentration in the liquid hydrocarbon stream is removed therefrom to provide the sulfone concentration lower than the sulfone concentration in the liquid hydrocarbon stream and the sulfone concentration in the acid phase.

9. A method according to any of the preceding claims, characterized in that the concentration of sulfone in the acid phase is in the above range of about 10 weight percent and the concentration of hydrogen fluoride in the acid phase exceeds about 80 by weight. cent in weight.

10. A method according to any of the preceding claims, characterized in that the concentration of sulfone in the "hydrocarbon phase" is less than about 100 ppmp.