MXPA01005106A - Branched alkyl-aromatic sulfonic acid dispersants for solubilizing asphaltenes in petroleum oils - Google Patents

Abstract

The present invention is an asphaltene dispersant containing an aromatic, a sulfonic acid head, and an alkyl tail containing 16 carbons or more and at least one branch of a methyl or longer alkyl. Preferably, the aromatic is a fused two ring aromatic and the tail is a two, branched alkyl tail of 30 carbons or longer.

Description

ACID DISPERSANTS AROMATIC ALLOY YOUR PHONIC BRANCHES TO SOLUBILIZE ASPHALT IN OIL OILS COMPENDIUM OF THE INVENTION The present invention refers to an additive that when combined with petroleum oils in low concentration, the tendency of the oil is to embed and fill the surface with carbon and this is reduced. This is achieved by increasing the solvency of asphaltenes, the least soluble fraction, in petroleum oil. It is well known that unrefined petroleum oils and oils containing asphaltene derived from unrefined petroleum oils have the tendency to deposit solid organics, called dirt and coal, on refinery process equipment that contacts the oil. The process equipment includes, but is not limited to, pipes, tanks, heat exchangers, furnace tubes, fractionators and reactors. Even small amounts of dirt or charcoal result in large energy loss due to much deficiency of heat transfer through dirt and carbon as opposed to metal walls alone. Moderate amounts of dirt and carbon cause high pressure drops and interfere with and operate the process equipment inefficiently. Finally, large amounts of dirt or carbon plug the process equipment to prevent the flow or otherwise make the operation intolerable, requiring stopping the equipment and cleaning it of dirt and carbon. It is also known that oil-containing asphaltene-containing oils that have undergone reaction at high temperatures, above 350 ° C, have a tendency to rapidly embed process equipment, when cooling or when combined with a more paraffinic oil. Such processed oils include, but are not limited to, the highest boiling distillation fraction after thermally or catalytically hydrothermally atmospheric or crude oil vacuum and the highest boiling fraction of the liquid product from the catalytic fractional distillation of the fluid , called tower bottoms for fractional distillation of catalyst or oil with catalyst impurities or clarified oil. This rapid incrustation is caused by asphaltenes that become insoluble when cooled or when combined with a more paraffinic oil. Here the asphaltenes are defined as the fraction of the oil that is soluble when the oil is combined with 40 volumes of toluene but insoluble when the oil is combined with 40 volumes of n-heptane. If the asphaltenes become insoluble at high temperatures, above 350 ° C, they rapidly form insoluble carbon in toluene. (see I. A. Iehe, Industrial &Engineering Chemistry Research, Vol. 32, 2447-2454). However, it is not well known that the mere combination of two or more unprocessed unrefined petroleum oils can cause the precipitation of insoluble asphaltenes that can rapidly embed the process equipment or when such combinations of unrefined oils are quickly heated above 350 ° C, the insoluble asphaltenes can fill the tubular heater tubes with carbon. If the combination of oils causes the precipitation of asphaltenes, the oils are said to be incompatible as opposed to compatible oils that do not precipitate asphaltenes when combined. Thus, incompatible combinations of oils have a much greater tendency to embed and fill compatible oils with carbon. If a combination of two or more oils have some proportion of the oils that precipitate asphaltene, the set of oils is said to be potentially incompatible. Fortunately, most unprocessed crude oil combinations are not potentially incompatible. It is only for this reason that many refineries can process crude oil for a long time without the need to stop and clean dirt and coal. Various unrefined oils have still been identified as - they are self-incompatible. This is contains insoluble asphaltenes yet not combined. However, once an oil or combination of incompatible oils is obtained, the rapid incrustation and coal filling that results normally requires stopping the refinery process in a short time. This results in a large economic charge because while the process equipment is being cleaned, large volumes of oil can not be processed. Therefore, it is desirable to increase the solubility of the asphaltenes in the unrefined oil. This can be achieved by adding asphaltene dispersants to unrefined oil.

SUMMARY OF THE INVENTION The present invention is an asphaltene dispersant containing an aromatic group, a sulfonic acid main group, and an alkyl tail containing 16 or more carbons and at least one branching of a methyl or longer alkyl. Preferably, the aromatic group is a fused aromatic of two rings and the tail a branched alkyl group of two tails of 30 carbons or longer. More preferably, the dispersant is a mixture with each alkyl tail varying from 1 to more than 30 carbons so that there is at least a total of 30 carbons in the tail and a branched methyl or a longer branch for every 12 carbons in the tail. tail. As well as these asphaltene dispersants need not be a pure compound but they can be a mixture of compounds of the above description, such as that prepared by reacting an aromatic stream derived from petroleum and a mixture of olefins or alcohols in the presence of a Friedel Crafts, such as AICI3, followed by sulfonation of the aromatic. These asphaltene dispersants are useful because they are added at low concentrations, one percent by weight or less and preferably less than 1000 parts per million, solubilize asphaltenes in petroleum oils or petroleum derivatives to prevent asphaltenes from being precipitated or adsorbed on metallic surfaces and thereby reducing their tendency to embed or fill coal with metal surfaces, especially heated metal surfaces, such as metal surfaces of heat exchanger and furnace tube.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a schematic diagram of the iso-naphthalene acid structure of C15-C15. Figure 2 shows a schematic diagram of a preferred asphaltene dispersant structure of the present invention.

DESCRIPTION OF THE PREFERRED MODALITY In the present invention it has been found that combining a member of a family of branched alkyl aromatic sulphonic acids is particularly effective in increasing the solubility of the asphaltenes in a petroleum derived oil. It is well known that alkylbenzene sulphonic acids are effective asphaltene dispersants (Chang and Fogler, Langmuir, 1TJ, 1749-1757) and are being sold commercially for that purpose. However, it has been found that these compounds with linear alkyl chain lengths above 16 carbons are not effective due to the lack of solubility in the oil. This leads to the conclusion that the optimum alkyl chain length is 12 carbons. However, it has been found that the reason for this lack of solubility is because the alkyl chains containing more than 16 carbons form crystals similar to wax and promote their precipitation from the oil. This leads to alkyl chains containing branched methyl esters that interfere with crystal formation. The result was that branched alkyl aromatic sulfonic acids become increasingly better asphaltene dispersants as the chain length of alkyl increased, and much better than linear alkyl aromatic sulfonic acids. It was then discovered that two branched alkyl chain tails bonded to aromatic sulfonic acids gave an additional boost in dispersing effectiveness. Finally, when comparing alkyl aromatic sulfonic acids of different sizes of aromatic rings, it was discovered that two fused aromatic rings are better dispersants than those that contain a ring (benzene) or three fused rings. This leads to the conclusion that the optimum alkyl aromatic sulfonic acid dispersant for asphaltenes is one which contains two branched alkyl, aromatic rings of two fused rings, and a main sulfonic acid. Figure 1 shows one with two tails of 15 carbons each and a methyl branch. The preferred dispersant would be a mixture of compounds with each tail varying from 1 to 15 carbons w the total number of carbons or sum of both tails, is 30 or more and with at least one methyl branch in each tail that is longer than 12 carbons. Thus, the preferred asphaltene dispersant is best defined by Figure 2 wherein R and Q are alkyl tails attached to a carbon that is attached at any position on the naphthalene ring. R and Q are alkyl chains with at least one branched methyl or longer alkyl groups per 20 carbons, and R + Q >; 29. Asphaltene dispersants are particularly useful in an oil compatibility method which allows potentially incompatible oil oil to be combined. This method, if it is described later, allows the determination of the effectiveness of a dispersant.

MEASURE OF EFFECTIVE DISPERSANTS The Oil Compatibility Method is based on tests with individual oils that involves combining with mixtures of a model solvent, toluene, and a non-solvent model, n-heptane. The Oil Compatibility Method and the tests provided with a method to quickly measure the capacity of a dispersant to increase the solubility of asphaltenes and to predict the improvement of the compatibility of any oil mixture without the need to interpret the results of the tests of thermal incrustation. The resulting increase in solubility of asphaltenes was measured by the decrease in equivalence of toluene, the percent of toluene (asphaltene solvent) in heptane (not asphaltene solvent) required to maintain the asphaltenes in the oil in solution. This has made it possible to quickly select the effectiveness of various synthetic and commercial additives as asphaltene dispersants.

OIL COMPATIBILITY METHOD Two or more tests of each petroleum oil with a test liquid containing different proportions of a non-polar asphaltene solvent and a non-polar asphaltene non-solvent can predict whether a given combination of oils is potentially incompatible. This is based on the determination of the Insolubility Number and the Solubility Combination Number for each petroleum oil in the combination using the petroleum oil tests. It is meant non-polar when the molecular structure of liquid only includes carbon, hydrogen, and sulfur atoms. Once again, it has been learned that potentially incompatible oils can be processed with little embedding or carbon filling as long as they are combined in the correct order, as predicted from oil tests, and as long as certain proportions of the oils in the The combination is avoided, as also predicted by the Insolubility Number and the Solubility Combination Number of each oil in the combination as determined by the oil tests. The first step of determining the Insolubility Number and the Solubility Combination Number for a petroleum oil is to establish whether the petroleum oil contains insoluble asphaltenes in n-heptane. This is achieved by combining 1 volume of the oil with 5 volumes of n-heptane and determining if the asphaltenes are insoluble. Any convenient method could be used. One possibility is to observe a drop of the combination liquid test mixture and oil between a glass slide and a glass coverslip using light transmitted with an optical microscope at an amplification of 50 to 600X. If the asphaltenes are in solution, few, if any, dark particles will be observed. If asphaltenes are insoluble, many dark particles will be observed, usually brown, usually 0.5 to 10 microns in size. Another possible method is to put a drop of the combination of the test liquid mixture and oil on a piece of filter paper and let it dry. If the asphaltenes are insoluble, you will see a ring or dark circle around the center of the yellow-brown spot made by the oil. If the asphaltenes are soluble, the color of the stain made by the oil will be relatively uniform in color. If the petroleum oil is found to contain insoluble asphaltenes in n-heptane, the procedure described in the following three paragraphs is followed to determine the Insolubility Number and the Solubility Combination Number. If it is not found that the petroleum oil contains insoluble asphaltenes in n-heptane, the Insolubility Number is assigned a value of zero and the Solubility Combination Number is determined by the procedure described in the section marked "Petroleum Oils without Asphaltene " Petroleum Oils Containing Asphaltene The Determination of the Insolubility Number and the Solubility Combination Number for a petroleum oil containing asphaltene requires testing the solubility of the oil in test liquid mixtures at the minimum ratios of two volumes of oil to liquid test mixture. The liquid test mixture is prepared by mixing two liquids in different proportions. A liquid is non-polar and a solvent for asphaltenes in the oil while the other liquid is non-polar and a non-solvent for the asphaltenes in the oil. Since asphaltenes are defined as being insoluble in n-heptane and soluble in toluene, it is more convenient to select the same n-heptane as the non-solvent for the test liquid and the toluene as the solvent for the test liquid. Although the selection of many other non-test solvents and test solvents can be made, their use does not provide a better definition of the preferred oil combination process than the use of n-heptane and toluene described herein. A convenient volume ratio of oil to test liquid mixtures is selected for the first test, for example, 1 ml. of oil to 5 ml., of the test liquid mixture. Then, various mixtures of the test liquid mixture are prepared by combining n-heptane and toluene in various known proportions. Each of these is mixed with the oil in the ratio of the selected volume of oil to liquid test mixture. Then it is determined for each of these if. Asphaltenes are soluble or insoluble. Any convenient method could be used. One possibility is to observe a drop of the liquid test mixture mixture and oil between a glass slide and a glass coverslip using light transmitted with an optical microscope at a magnification of 50 to 600X. If the asphaltenes are in solution, few, if any, dark particles will be observed. If asphaltenes are insoluble, many dark particles will be observed, usually brown, usually 0.5 to 10 microns in size. Another possible method is to put a drop of the combination of the test liquid mixture and oil on a piece of filter paper and let it dry. If the asphaltenes are insoluble, you will see a ring or dark circle around the center of the yellow-brown spot made by the oil. If the asphaltenes are soluble, the color of the stain made by the oil will be relatively uniform in color. The results of combining the oil with all test liquid mixtures are ordered according to the increased percent of toluene in the liquid test mixture. The desired value will be between the minimum percent of toluene that dissolves asphaltenes and the maximum percent of toluene that precipitates asphaltenes. They prepare more test liquid mixtures with toluene percent between these limits, it is combined with oil in the selected volume ratio of oil to liquid test mixture, and it is determined if the asphaltenes are soluble or insoluble. The desired value will be between the minimum percent of toluene that dissolves asphaltene and the maximum percent of toluene that precipitates asphaltene. This process is continued until the desired value is determined within the desired precision. Finally, the desired value is taken by making the average of the minimum percent of toluene dissolving asphaltenes and the maximum percent of toluene that precipitates asphaltenes. This is the first data point, i, to the selected volume ratio of oil to liquid test mixture, Ri. This test is called the toluene equivalency test. The second data point can be determined by the same process as the first data point, only by selecting a different ratio of oil volume to liquid test mixture. Alternatively, a percent of toluene below that determined for the first data point can be selected and that liquid test mixture can be added to a known volume of oil until the asphaltenes just begin to precipitate. At that point the ratio of oil volume to liquid test mixture, R2, to the selected percent of toluene in the test liquid mixture, T2, becomes the second data point. Since the precision of the final numbers increases as the second data point further deviates from the first data point, the preferred test liquid mixture for determining the second data point is 0% toluene or 100% n-heptane. This test is called the heptane dilution test.

The Insolubility Number, IN, is given by: and the Solubility Combination Number, SBN is given by: Petroleum Oils without Asphaltenes If the petroleum oil does not contain asphaltenes, the Insolubility number is zero. However, the determination of the Solubility Combination Number for a petroleum oil that does not contain asphaltenes requires using a test oil containing asphaltenes for which the Insolubility Number and the Solubility Combination Numbers have been previously determined, using the procedure just described. First, 1 volume of test oil is combined with 5 volumes of petroleum oil. Insoluble asphaltenes can be detected by the microscope or stain technique, described above. If the oils are very viscous (greater than 100 centipoise), they can be heated to 100 ° C during the combination and then cooled to room temperature before searching for insoluble asphaltenes. Also, the stain test can be done on a combination of viscous oils in an oven at 50-70 ° C. If insoluble asphaltenes are detected, the petroleum oil is a non-solvent for the test oil and the procedure in the following paragraph should be followed. However, if insoluble asphaltenes are not detected, the petroleum oil is a solvent for the test oil and the procedure in the paragraph following the next paragraph should be followed. If insoluble asphaltenes are detected when 1 volume of the test oil is combined with 5 volumes of the petroleum oil, small volume increases of the petroleum oil are added to 5 ml of the test oil until the insoluble asphaltenes are detected. The volume of the non-solvent oil, VNso / is equal to the average of the total volume of oil oil added for the volume increase just before insoluble asphaltenes were detected and the total volume added when the insoluble asphaltenes were detected first. The size of the volume increase can be reduced to that required for the desired accuracy. This is called the dilution test of non-solvent oil. If SBNT0 is the Solubility Combination Number of the test oil and INTO is the Insolubility Number of the test oil, then the Solubility Combination Number of the non-solvent oil, SB / is given by: 5 [S BNTO ~~ I TO BN = - S • JBNTO If insoluble asphaltenes were not detected when 1 volume of the test oil was mixed with 5 volumes of the petroleum oil, the petroleum oil is a solvent oil for the test oil. The same ratio in oil volume to RTo test liquid mixture is selected, as used to measure the Insolubility Number and the Solubility Combination Number for the test oil. However, various mixtures of the test liquid are now prepared by combining different known proportions of the petroleum oil and n-heptane in place of toluene and n-heptane. Each of these is mixed with the test oil at a ratio of oil volume to liquid test mixture equal to Rto- Then it is determined for each of these if the asphaltenes are soluble or insoluble, such as by the test methods of microscope or spot discussed previously. The results of combining oil with all test liquid mixtures are ordered according to the percent increase of petroleum oil in the liquid test mixture. The desired value will be between the minimum percentage of 'petroleum oil dissolving asphaltenes and the maximum percent of petroleum oil that precipitates asphaltenes. More test liquid mixtures are prepared with percent petroleum oil within these limits, combined with oil in the selected volume ratio of oil to liquid test mixture (Rto) and determined whether the asphaltenes are soluble or insoluble. The desired value will be between the minimum percent of petroleum oil dissolving asphaltene and the maximum percent of petroleum oil that precipitates asphaltene. This process is continued until the desired value is determined within the desired precision. Finally, the desired value is taken by making the average of the minimum percent of petroleum oil dissolving asphaltenes and the maximum percent of petroleum oil that precipitates asphaltenes. This is the data point, so to the selected volume ratio of test oil to liquid test mixture, RTo- This test is called the solvent oil equivalency test. If Tto is the data point measured previously to the ratio in volume of test oil to liquid test mixture, RTO / on test oil with test liquids composed of different ratios of toluene and n-heptane, then the Number of Oil Solubility Combination SBN, is given by: Oil Oil Blends Once the Solubility Combination Number for each component is determined, the Solubility Combination Number for an oil blend, SBNmiX, is given by: lSßNl + V2SBN2 + V3 SBN3 + SßNmix = Vi + V2 + V3 + where Vi is the volume of component 1 in the mixture. The criterion for compatibility for a mixture of petroleum oils is that the Solubility Combination Number of the oil blend is greater than the Insolubility Number of any component in the mixture. Therefore, a combination of oils is potentially incompatible if the Solubility Combination Number of any component oil in that combination is less than or equal to the Insolubility Number of any component in that combination. Once asphaltenes precipitate, it takes from the order of hours to weeks for the asphaltenes to redissolve while it takes the order of minutes to process the oil in refinery equipment. Thus, to prevent fouling and coal filling a potentially incompatible combination of oils must be combined to always maintain the Solubility Combination Number of the mixture higher than the Insolubility Number of any component in the combination. Thus, the order of combination and the final proportions of oils in the combination are important. If one starts with the highest Solubility Combination Number oil and combines the remaining oils in the order of decreasing the Solubility Combination Number and if the final mixture satisfies the compatibility criteria of the Solubility Combination Number of the mixture, greater than the Solubility Number of any component in the combination, then the compatibility of the oils through the combination process is ensured even when the combination of oils is potentially incompatible. The result is that the combination of oils will produce incrustation and / or minimum carbon fill in the subsequent processing.

EXAMPLE 1 The effect of 1% by weight and 5% by weight of alkyl benzene sulphonic acids on the reduction of toluene equivalence in Baytown Cat Cracker Bottoms is shown in Figure 3. While a g tail reduces the equivalence of toluene (TE) for a short time, tails much longer than 12 carbons were required for the dispersion to last as long as one day and present long-term stability. However, tails longer than 16 carbons resulted in a dispersant that was only partially soluble in the oil because the tails crystallized as a wax. A branched C 24 benzene sulphonic alkyl acid showed better performance in terms of TE reduction and long-term stability. In addition, the acid * Branched 24 carbon benzene sulphonic tail is an intermediate in the manufacture of lubricating oil detergents (Exxon Chemicals Paramins) and is named SA119. to. C8 - 1% reduced TE from 87 to 60, insoluble the next day - 5% reduced TE from 87 to 55, insoluble the next day b. C12 - 1% reduced TE from 87 to 60, insoluble the next day - 5% reduced TE from 87 to 55, soluble the next day c. Cie - is a solid and partially soluble in toluene / heptane d. IsoC24 (5 branched methyl) - 1% reduced TE from 87 to 60, soluble the next day - 5% reduced TE from 87 to 55, soluble the next day. Thus, branched alkyl benzene sulphonic acids are better than linear alkyl benzene sulphonic acids as asphaltene dispersants in unrefined oil.

EXAMPLE 2 Table 1 contains the results of synthesized dispersants. The synthesis involves the alkylation of an aromatic ring, followed by sulfonation. The variables in the synthesis are the type of aromatic and the type of olefin used for alkylation. The alpha olefins give a simple tail whereas the internal olefins give two tails with a distribution of separations of the length of the total chain between the two tails. further, the total number of carbons and the degree of branching of the olefins was varied. 13C NMR was used to measure the chain length, methyl branches per molecule, percent of olefin sample that was olefin, and the percent of aromatics that were functionalized by the addition of an olefin. Elemental analysis was used to determine the percent sulfonation. Finally, the reduction in toluene equivalence of the unrefined Maya oil was used after the addition of 5% dispersant to measure the effectiveness as an asphaltene dispersant. The results in Table 1 illustrate the salient features of the invention. (a) When comparing Entries 3, 16 and 23 with the same alpha olefin, the dispersant with naphthalene results in a lower toluene equivalency than with toluene or phenanthrene. In addition, when comparing 7 and 8 with 24 or 9 with 25, naphthalene gives better results than phenanthrene. (b) When comparing Input 20 and 21 with 14 or input 19 with 1, it is clear that naphthalene is a structure of two aromatic rings fused in an upper performer compared to two aromatic rings that are connected by a CC link (binaphthyl ) or tetralin where one ring is aromatic and the other is non-aromatic. (c) Since the best dispersants were prepared with internal olefins, two tails are more effective than simple tails. (d) Since internal olefins of longer chain length produced the best dispersants as seen by 7, 8, 10 and 11 with carbon chains of 37 to 47 on naphthalene, the alkyl tails of at least 30 carbons are more effective (e) When comparing 12 and 14, one sees that the more branched tail produces a better dispersant even with a low degree of functionalization.

TABLE 1 - Examples of Synthetic Asphthalate Dispersants Length% Equival Olefin Methyls Function No. Internal Aromatic or chain by ali-Maya alpha? Molecule Tolueno Carbon a 1 Internal Toluene 23 0.15 119 34 2 Internal Toluene 23 0.15 78 31 3 Tolueno Alfa 21 0 76 34 4 Internal Toluene [20-24] [0.33] 78 32 Internal Toluene 25 0 36 32 6 Internal Toluene 33 0.99 37 23.5 Internal Naphthalene 37 0.33 29 13 Internal Naphthalene 37 0.33 114 11 Internal Naphthalene 33 0.99 44 17 Internal Naphthalene 47 0.28 85 11 Internal Naphthalene 37 0.54 90 13 Naphthalene Internal 25 1.9 51 17 Internal Naphthalene 18 0.10 95 31 Internal Naphthalene 23 0.15 89 23 Naphthalene Internal 18 0.17 65 32 Naphthalene Alfa 21 0 86 28 Internal Naphthalene 29 0.33 60 32 Naphthalene Alfa 17 0.04 40 26 Internal Tetralin 37 0.33 76 > 36 Internal Tetraline 23 0.15 103 29 Binaftilo Internal 23 0.15 119 > 30 Phenanthrene Internal 23 0.15 62 30 Phenanthrene Alfa 21 0 34 34 Phenanthrene Internal 37 0.33 43 26.5 Internal Fenantrene 33 0.99 62 29

Claims (7)

1. CLAIMS 1. A dispersing composition of asphaltene comprising an aromatic, a main sulfonic acid, and one or more alkyl tails including at least 16 carbons and at least one branching of an alkyl group.
2. 2. The composition of claim 1, wherein the aromatic is two fused rings.
3. 3. The composition of claim 1, wherein the glue is a double branched alkyl tail of at least 30 carbon atoms.
4. 4. The composition of claim 3, wherein each branching of the alkyl tail includes one alkyl branch for every 20 carbon atoms.
5. The composition of claim 3, wherein each branching of the alkyl tail includes one alkyl branch for every 12 carbon atoms.
6. 6. The composition of claim 1, wherein the alkyl group is a methyl group.
7. 7. A method for dispersing asphaltenes in a petroleum-derived oil comprising adding to the oil 10 to 1000 ppm of an alkyl aromatic sulfonic acid compound including an aromatic, a primary sulfonic acid, and one or more alkyl tails including at least 16 carbons and at least one branch of an alkyl group.