MXPA98001373A - Procedure to reduce the corrosivity and acidity of crudes del petro - Google Patents

Abstract

The invention relates to a process for treating crude oils or fractions thereof, to reduce or eliminate their corrosivity by the addition of suitable amounts of oxides, hydroxides, hydrates of hydroxides or salts of naphthenate of metals of Group IA or Group IIA to a corrosive, acidic crude oil, or by remixing a crude oil containing a salt of naphthenate, in appropriate ratios, with a corrosive, acidic crude oil. The procedure has the benefits of reducing the problems of material handling, associated with the treatments of crude oils, which use liquid solvents, and reducing the formation of emulsion.

Description

PROCEDURE TO REDUCE THE CORROSIVITY AND ACIDITY OF OIL CRUDES This application is a partial continuation of Serial No. E. U. A., 655.261, filed June 4, 1996, Serial No. E.U.A., 597.310, filed on February 6, 1996 and Serial No. E. U. *. , 519,554, filed on August 25, 1995. FIELD OF THE INVENTION The present invention relates to a process for decreasing the acidity and corrosivity of crude and crude fractions containing petroleum acids.

BACKGROUND OF THE INVENTION Many crude oils, with a high content of organic acid, such as the complete crude oils containing naphthenic acids, are corrosive to the equipment used for the extraction, transportation and processing of the crude oil, such as the distillation lines and transfer. Efforts to minimize the corrosion of naphthenic acid have included a number of approaches. The patent of E. U. A., No. 5,182,013, refers to such recognized approaches, such as mixing oils with greater content of naphthenic acid with oils of low content of naphthenic acid. Additionally, a variety of attempts have been made to address the problem by replacing carbon or low alloy steels with more expensive, highly alloyed stainless steels that use corrosion inhibitors for metal surfaces of equipment exposed to acids, or by neutralizing and removing the acids from the oil. Some inhibiting companies have claimed that the use of specific inhibitors of organic corrosion, based on sulfur and phosphorus, can be effective in reducing corrosion by naphthenic acids. Examples of such technologies include the treatment of metal surfaces with corrosion inhibitors, such as polysulphides (U.S. Patent No. 5,182,013) or oil-soluble reaction products of an alkynediol and a polyalkene polyamide (US Pat. , No. 4,647,366) and the treatment of a liquid hydrocarbon with a dilute aqueous alkaline solution, specifically, the dilute aqueous and dilute NaOH or KOH (U.S. Patent No. 4,199,440). The U. A. patent, No. 4,199,440, however, notes that a problem arises with the use of aqueous solutions containing higher concentrations of an aqueous base. These solutions form emulsions with the oil, requiring the use of only basic aqueous and diluted solutions. U.S. Patent No. 4,300,995 discloses the treatment of carbonaceous materials, particularly coal and its products, such as heavy oils, vacuum gas oil and petroleum residues, which have acidic functionalities, with a tertiary base, such as hydroxide. tetramethylammonium, in a liquid (alcohol or water). Additional processes using aqueous solutions of alkali hydroxides include those described in Kalichevsky and Kobe, in Petroleum Refining With Chemicals, (1956) Ch. 4, as in the US patents, Nos. 3,806,437, 3,847,774, 4,033,860, 4,199,440 and 5,011,579; German patents 2,001,054 and 2,511,182; Canadian Patent 1,067,096; Japanese Patent 59-179588; the Romanian patent 104,758 and the Chinese patent 1,071,189. Certain treatments have been practiced in mineral oil distillates and hydrocarbon oils (for example with lime, molten NaOH or KOH, certain highly porous calcined salts of carboxylic acids suspended in carrier media). Total crude oils were not treated. The patents of E. U. A., No. 2,795,532 and 2,770,580 (Honeycutt) disclose processes in which the "heavy mineral oil fractions" and the "petroleum vapors" are treated respectively. The '532 patent further discloses that the "intermittent vapors" are contacted with a "liquid alkaline material", which contains, among others, alkali metal hydroxides, and "liquid oil". A mixture of only NaOH and KOH, in molten form, it is described as the preferred treatment agent, however, "other alkaline materials, for example lime, can also be used in minor amounts". Importantly, the * 532 does not describe the treatment of total crudes or fractions that boil over 565se. Rather, the '532 patent treats only condensed vapors and vapors of fractions less than 565SC, s dec -, fractions that can be vaporized under the conditions described in this' 532 patent. Petroleum residues and other non-vaporizable fractions (with process conditions of the patent * 532), which contain naphthenic acids, can not be treated by the process. Since naphthenic acids are distributed through the crude fractions (many of which are not vaporizable) and since the crude ones differ widely in the content of the naphthenic acid, the '532 patent did not provide an expectation that could be capable of treating Successfully an extensive list of crudes with a variety of boiling points. In the patent of E.V.A., No. 2,068,979, it is disclosed that naphthenates were used to prevent corrosion in petroleum distilleries. The patent teaches the addition of calcium naphthenate to petroleum to react with and purify strong free acids, such as hydrochloric and sulfuric acids. This was attempted to prevent corrosion in the distillation units by these strong acids and makes no claim with respect to naphthenic acids. In fact, naphthenic acids have been formed when strong acids are converted into salts. Some prior art involves the addition or formation of calcium carbonate dispersions (Cheng et al., U.S. Patent No. 4,164,472) or magnesium oxide (Cheng et al., U.S. Patent Nos. 4,163,728, 4,179,383 and 4,225,739. ), co or corrosion inhibitors in fuel products and lubricating oil products, but not in complete crude oils or primary distillation. Similarly, Mustafaev et al. (Azerb.Inst, Neft. Khim (1971) 64-6) report improved detergency and anticorrosive properties of calcium, barium and zinc hydroxide additives in lubricating oils. The amino naphthenates (asson et al., U.S. Patent No. 2,401,993) and the zinc naphthenates (Johnson et al., U.S. Patent No. 2,415,353, Rounault, U.S. Patent No. 2,430,951 and Zisman et al. US Patent No. 2,434,978) are also claimed as anti-corrosive additives in various lubricating oil products. Another use of calcium compounds with petroleum includes the removal of naphthenic acids from hydrocarbon oils by the extraction of limestone on glass (Elkin et al., Soviet Union 1,786,060) or by metal oxides related to hydrotalcites ( Gillespie et al., U.S. Patent No. 5,389,240). Finally, calcium hydroxide (Kessick, Canadian patent 1,249,760 helps in the separation of water from the waste of heavy crude oils.) While these processes have achieved several degrees of success, there is a continuing need to develop more efficient methods to reduce the acidity and corrosivity of whole crudes and their fractions, particularly residues and other fractions that distill more than 3432C.

SUMMARY OF THE INVENTION The present invention provides: a method for decreasing the corrosivity of a corrosive crude oil containing acid, this method comprises: contacting the starting, acid-containing, corrosive crude oil with an effective amount of a salt of Naphthenate of a metal of the TIA Group, to produce a treated crude oil that has a decreased corrosivity and a method to decrease the corrosivity of a corrosive crude oil, which contains acid, this method comprises: mixing a crude starting corrosive oil, containing acid, with an effective amount of a second crude oil treated with a metal naphthenate, in which the metal naphthenates are selected from Group IA and IIA, to produce a final treated crude oil, which has a decreased corrosivity. The present invention may suitably comprise, consist or consist essentially of the described elements and may be practiced in the absence of an element not described.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the corrosion rate of a crude oil as a function of the calcium concentration for Example 7. Figure 2 shows the corrosion rate for the crude oil versus the neutralization percentage of the naphthenic acid for Example 8; Figure 3 shows the corrosion rate for the fraction of the boiling crude oil at 418-521SC versus the percentage of naphthenic acid neutralization for Example 9.

DETAILED DESCRIPTION OF THE INVENTION Some of the complete crude oils contain organic acids, such as carboxylic acids, which contribute to the corrosion or fouling of the refinery equipment. These organic acids are generally in the category of naphthenic acids and other organic acids. Naphthenic acid is a generic term used to identify a mixture of organic acids present in petroleum materials. Naphthenic acids can cause corrosion at temperatures ranging from about 65 to 4202C. These naphthenic acids are distributed through a wide range of boiling points (ie, fractions) in the crude oils containing acids. The present invention provides a method for broadly removing these acids and, more conveniently, heavier fractions (higher boiling point) and liquids, in which these acids are often concentrated. The naphthenic acids may be present either alone or in combination with other organic acids, such as phenols. Complete crude oils are very complex mixtures, in which a large number of competent reactions can occur. Unexpectedly, the reactions occur even though the acid is diluted compared to the large excesses of the crude oil and other reactive species, typically present. And conveniently, the resulting naphthenate salts remain soluble in the oil and tend to concentrate in the waste rather than concentrate in the minor boiling secondary streams.

The process of the present invention has utility in processes in which inhibition or corrosion control of the liquid phase is desired, for example metal surfaces. More generally, the present invention can be used in applications where a reduction in acidity, typically, as evidenced by the decrease in the number of acid crude neutralization or a decrease in the intensity of the carboxyl band in the spectrum Infrared at approximately 1708 cm-1 of the crude oil treated (neutralized), would be beneficial and in which the formation of the oil-water emulsion and the large volumes of solvent are not convenient. The present invention also provides a method for controlling the formation of the emulsion in acidic crudes, by the treatment of a major contributing component of such emulsions, naphthenic or similar organic acids, and reducing the inherent process problems of handling and processing. The concentration of the acid in the crude oil is typically expressed as an acid neutralization number or an acid number, which is the number of milligrams of KOH required to neutralize the acidity of one gram of the oil. It can be determined in accordance with ASTM D-664. Typically, the decrease in acid content can be determined by a decrease in the neutralization number or in the intensity of the carboxyl band in the infrared spectrum at about 1708 cm -1. Crude oils with total acid numbers (TAN) of approximately 1.0 mg KOH / g and lower, are considered to be of moderate to low corrosivity (crude with a total acid number of 0.2 or less, are generally considered to be corrosive low) . Crude oils with total acid numbers greater than 1.5 are considered corrosive. TANs are measured by the ASTM Method D-664. Acidic crudes having free carboxyl groups can be effectively treated using the process of the present invention. IR analysis is particularly useful in cases where a decrease in the number of neutralization is not in treatment with the base, and there is a sufficient measure of acidity, as has been found to occur in treatment with bases weaker than KOH. The crudes that can be used are any crude oil containing naphthenic acid, which is liquid or can be liquefied at temperatures in which the present invention is carried out. As used herein, the term "full or total crudes" means unrefined, undistilled crudes. As used herein, the term "stoichiometric amount" means a sufficient amount of the metal hydroxide oxide, hydroxide or hydrate, on a molar basis, to neutralize one mole of acid functionality in the crude oil. In moles, in the case of the oxides, hydroxides and hydrates of Group IA hydroxides, the ratio is 0.5 to 1 mol of metal to the acid functionality. The terms "above", "greater than" or "in excess of" the stoichiometric amount, are defined in relation to the above, as well as the term • sub-stoichiometric. "The sub-stoichiometric ranges from 0.025: 1 moles to a stoichiometric amount, preferably 0.25: 1 to less than 0.5: 1 (ie, a stoichiometric amount) for Group IIA, Group IA, is 0.05: 1 moles to less than 1: 1 (ie a stoichiometric amount) , preferably 0.5: 1 to less than 1: 1 moles A larger than stoichiometric amount may vary up to 10: 1 moles for Group IA and IIA, preferably up to 5: 1 for Group I. Preferred metals are the sodium, lithium and potassium for Group IA, and calcium, magnesium, barium and strontium for Group IIA, with calcium and magnesium being preferred and more preferred is calcium Contact is typically carried out at any ambient temperature or at a high enough temperature for the reflux of the solution n. Typically, the range is up to 2002C, with narrower ranges suitably being about 20 to 2002C, preferably from 50s to 200SC, and more preferably 75 to 1502C.

Corrosive acidic crudes, ie those containing naphthenic acids alone or in combination with other organic acids, such as phenols, can be treated according to the present invention. The acidic crudes are preferably full crudes. However, acid fractions of the whole crudes, such as the primary distillation and other high boiling fractions, can also be treated. Thus, for example, fractions of 260SC, fractions of 343 dC and higher, vacuum gas oils and more conveniently fractions of 565SC and crude primary distillation can be treated. 1. Treatment of Rust, Hydroxide and Hydroxide Hydrate In one aspect of the invention, the crude was contacted with an effective amount of a compound containing a metal of Group IA or Group IIA, i.e. an oxide, a hydroxide or a hydroxide of an alkali metal or an alkaline earth metal hydroxide, in the presence of an effective amount of water, which, when present, can be added or occurs naturally, to produce a treated crude having a corrosiveness and acidity diminished. The material is added as a solid, which may also include an aqueous paste of a solid in a liquid, a solid in water or a solid in an organic liquid aqueous paste or in an aqueous suspension. The processes of the present invention can be used to produce treated crudes having a decreased corrosivity and a naphthenic acid content which is either completely neutralized or partially neutralized, depending on the ratio and type of hydroxide, hydroxide or hydroxide hydrate used to treat this acidic acid. The metal oxide of Group IA and IIA and mixtures thereof, the hydroxide and its mixtures or the hydrate of the hydroxide and mixtures thereof, are added to the crude containing acid in an effective molar ratio to produce the neutralized or partially neutralized crude oil (ie say, not corrosive); the neutralization can be total or partial, as desired. The reduction of corrosion and decrease in acidity is influenced by the amount of added hydroxide, hydroxide or hydroxide hydrate. In general, the addition range is from a sub-stoichiometric amount to 10: 1 moles per mole of acid. More specifically, it can be added in a ratio of the oxide or its mixtures, hydroxide or its mixtures, or hydroxide hydrate or its mixtures of Group IA metal from 0.05 moles to less than 1: 1 moles per mole of acid, of 0.5: 1 to less than 1: 1 moles, from 1: 1 to 10: 1. For Group IIA, the interval may be shorter. Typically ratios of the oxide or its mixtures, hydroxide or its mixtures, or hydroxide hydrate or its mixtures, of the metal of Group IIA, to the total acid of 0.025 moles up to a stoichiometric amount, or of 0.25 moles less than the stoichiometric amount, until 10: 1 moles, but ratios from 0.5: 1 to 5: 1 and from 1: 1 to 0.5: 1 can also be used. The addition of smaller amounts (of the stoichiometric) of the oxides, hydroxides or hydrates of hydroxides of the metals of Group IA or Group IIA, may result in an incomplete (ie partial) neutralization of the starting acid crude. CaO and Ca (OH) 2- are preferred. Some raw materials contain a sufficient amount of water, others require the addition of water at the intervals specified herein. The total amount of water is an effective amount from 0 to 7% by weight of the crude. The total amount of water for the compounds containing the Group IIA metal varies from at least 0.3% (based on the oil containing acid), more preferably from 0.3% to 7%, but can be found within the following Intervals: 0.2-1.5% by weight, 0.3-1.2% and 0.6-1%. When the metal hydroxide oxides, hydroxides and hydrates of Group IA are sanitized, they do not require the addition of water, but may be used in the absence or presence of water within the ranges specified for Group IIA. The treatments produce treated crudes that have a decreased corrosivity and a reduced acidity, which can vary from partial neutralization to the essential absence of acidity, depending on the treatment. The anhydrous acid crudes can be treated by contacting the crude with an effective amount of the metal-containing compound, selected from the oxides, hydroxides, hydroxide hydrates of Group IIA metals, or mixtures of the oxides, hydroxides, hydrates of hydroxides , in the presence of a corresponding sufficient quantity of water, to make the base effective to neutralize the acid. Thus, a small amount of water may be present for the effective reaction, when the oxides, hydroxides and hydrates of Group IIA metal hydroxides are used. The formation of a crude oil-water emulsion (ie, water in oil or oil in water) tends to interfere with the efficient separation of crude oil and water aces and so on. with the recovery of the treated crude oil. The emulsion formation is inconvenient and a particular problem is encountered during the treatment of the naphthenic acid-containing crudes with aqueous bases. The processes of the present invention can be carried out in the essential absence of emulsion formation. Thus, an additional benefit of the treatment is the absence or substantial absence of the emulsion formation. The oxides, hydroxides and hydrates of Group IA and IIA metal hydroxides can be purchased commercially or synthesized using known methods. In solid form, they may be in the form of a powder or a compound with particles sized or supported in a refractory matrix (ceramic). Typical hydroxides include KOH, NaOH, calcium hydroxide, lithium hydroxide monohydrate and barium hydroxide octahydrate, while oxides include calcium oxide, sodium oxide and barium oxide. Calcium oxide and hydroxide are preferred. Certain solids typically occur as hydrate crystals. The reaction times depend on the temperature and nature of the crude to be treated, its acid content and the amount and type of Group IA or IIA metal oxide, the added hydroxide hydrate, but typically can be for less than 1 hour to about 20 hours, to produce a product that has a decrease in corrosivity and acid content. The treated crude contains naphthenate salts of the oxides, hydroxides and hydrates of Group IA or IIA metal hydroxides, used in the treatment. 2. Treatment of Naphthenic Acid Salt In another aspect of the invention to reduce the corrosivity of crude oils, the decrease in corrosivity and acidity is achieved by processes that include direct addition or in situ generation of the metal carboxylates in the corrosive oils Metal carboxylates, whose thermodynamic stability equals or exceeds the stability of iron carboxylates, are useful in this invention. Preferred metals belong to the alkaline-earth class, ie Ca, Mg, Ba and Sr. The starting acid crude oils for the treatment of the naphthenic acid salt have a water content of less than 0.3% by weight, more preferably , this water content is between 0.3% and 7% by weight. For direct addition, the salt of the metal naphthenate is added in an effective amount of up to 5: 1 moles of metal to the acid functionality in the crude oil. Specifically, in this aspect of the invention, the corrosivity of a corrosive crude containing acid is decreased by contact with the starting corrosive crude oil containing acid with an effective amount of a naphthenate salt, selected from the group consisting of the salts, complete and partial, of the metal naphthenate of Group IIA (such as the i-salts). Additionally, the metal naphthenate salt can be added by mixing a raw crude oil containing acid with a second crude oil containing metal naphthenate, or a fraction ("crude oil treatment"). The metal naphthenate salts are obtained in situ, as described in "1. Treatment of oxides, hydroxides and hydrates of hydroxides" < _-. this section. The neutralized crude can be neutralized completely or partially, depending on the ratio of metals to the acid functionality used to produce it. The metals are Group IA and Group IIA metals, as discussed previously. Crude from treatments containing an effective amount of the naphthenate salt is used, but practically this means that the ratio of the metal naphthenate in the acid treatment crude to the starting crude containing acid will be less than 1: 1. moles However, in practice, an amount of the naphthenate salt is added in a ratio of 0.025: 1 to 1: 1 moles of the metal based on the acid content of the starting acid crude, more typically 0.25 to 1: 1 moles is used. Ratios greater than 1: 1 and typically 10: 1 moles of metal to the acid content can also be used, however, the naphthenate salt in excess of that produced by the in situ neutralization in the crude treatment may need be added Thus, the reduction of the acidity and corrosivity of the starting crude can be achieved to the desired degrees by altering the ratio of the starting crude oil containing acid to the naphthenate salt, generated by the addition in situ or by direct addition and / or mixture with the second crude containing naphthenate (that is, neutralized). The acidic starting crude and the second naphthenate-containing crude must have comparable intervals and? -activity from the boiling point. Thus, for example, a total acid crude must be mixed with a complete crude containing naphthenate, a fraction of 260sc with a corresponding fraction, a fraction of 3432C and more with a corresponding fraction, a fraction of 565SC and more with a corresponding fraction , a vacuum gas oil with a corresponding vacuum gas oil, a primary distillation crude with a primary distillation crude, and the like. Significantly, when in situ generation is practiced, the process involves adding a metal oxide or hydroxide to the crude starting oil containing acid, in sub-stoichiotic quantities, to form the corresponding naphthenate. Thus, in another aspect, an alkaline earth metal oxide, in particular CaO or calcium hydroxide, are added in stoichiometric amounts to the crude oil, which contains carboxylic acids, naphthenic acid in particles. By this, it means that less CaO or calcium hydroxide is added than necessary to completely neutralize the acids. While not wishing to be bound by any particular theory, it is believed that the sub-stoichiometric addition of Ca can suppress corrosion in two ways: (1) the initial neutralization of some naphthenic acids and (2) the suppression of H + in the acids remaining, due to the effect of common ions. The Ca preferably reacts with stronger naphthenic acids. The hypothesis of the effect of Ca on corrosion is given below. The hydrogen ion (H +) is believed to be an impeller for the corrosion reaction: Fe ° + 2H + - Fe ++ + H2 The reaction of CaO with naphthenic acid requires and also produces H2O, according to: CaO + 2RC00-H ~ (RCOO) 2-Ca + H20 Next, with some of the H20 present, the naphthenic acids, weakly ionized, are a source of H +, according to RCOO-H - H + + RCOO * Ca naphthenates form additional naphthenate ions (following equation) to shift the acid balance to the left, decreasing the concentration of H + by the common ion effect (RCOO) 2-Ca - > (RCOO) -Ca + + RCOO- - Ca ++ + 2RC00".

F ^ o results in a decrease in disproportionate H + concentration, if the dissociation of the salt is greater than the dissociation of the acid. Beneficially, the formation of the emulsion can be reduced or essentially absent in the previous treatments. The present invention can be demonstrated with reference to the following non-limiting examples.

Example 1 The reaction apparatus was a 200 ml fluted glass vessel equipped with stirrer and reflux condenser. Gryphon crude (150 g), which has a total acid number of 4 mg KOH / g, was placed inside the reactor. 150 g of Gryphon contain 10.7 milliequivalents of acids. 300 mg of calcium oxide were added, corresponding to 5.35 millimoles or 10.7 milliequivalents. Then the mixture was brought to 100SC and stirred for 7 hours. The infrared examination showed no change in the bands at 1708 cm -1 and 1760 cm -1, which correspond to the dimeric and monomeric forms of the acid, compared to the untreated Gryphon. 1.5 ml of water was added. After 30 minutes, infrared examination showed that the bands at 1708 and 1760 cm -1 had disappeared, ie, the acids were neutralized.

Example 2 The reaction apparatus was the same as in Example 1. 50 g of the Heidrun crude, which has a total acid number of 2.9 mg KOH / g, were placed inside the reactor. 50 g of Heidrun contain 2.5 milliequivalents of acids. 70 mg of calcium oxide, corresponding to 1.25 millimoles or 2.5 milliequivalents, were added. Then the mixture was stirred at 100 ° C for 7 hours. The infrared examination showed no change in the intensity of the bands at 1708 and 1760 cm "1, which correspond to the dimeric and monomeric forms of the acids, compared to the untreated Heidrun 0.5 ml of water was added and the mixture was stirred at 100 ° C. for 30 minutes, infrared examination showed that the bands at 1708 and 1760 cm -1 had disappeared, ie, the acids had been neutralized.

Example 3 The reaction apparatus was a 300 ml glass reactor, equipped with stirrer, Dean-Stark trap and reflux condenser. 200 ml of San Joaqui Valley crude, which has a total acid number of 4.2 mg KOH / g, was placed inside the reactor and heated to 120SC until no more water condensed in the Dean-Stark trap, which took around 4 hours 100 g of San Joaquim Valley anhydrous crude, thus obtained, were placed inside the same reactor used in Example 1. 100 g of San Joaquim Valley crude contain 7.5 milliequivalents of acids. ? ° added 210 mg of calcium oxide to the crude, corresponding to 3.75 millimoles or 7.5 milliequivalents. Then the mixture was stirred at 100 ° C for 5 hours. The infrared test showed no change in the intensity of the bands at 1708 and 1760 cm-1, which correspond to the dimeric and monomeric forms of the acid, compared to the untreated San Joaquim Valley crude. 1 ml of water was added. After stirring at 100 ° C for 30 minutes, the infrared examination showed that the bands at 1708 and 1760 cm "1 had disappeared, which shows the neutralization of the acids.

Example 4 The reaction apparatus was a 300 ml glass reactor, equipped with stirrer, Dean-Stark trap and reflux condenser. 200 ml of Bolobo 2/4 crude, which has a total acid number of 8.2 mg KOH / g was placed inside the reactor and heated to 150SC until no more water condensed in the Dean-Stark trap, which took about 4 hours. 100 g of the Bolobo 2/4 anhydrous crude, thus obtained, were placed inside the same reactor used in Example 1. 100 g of the Bolobo 2/4 crude contains 14.6 milliequivalents of acids. 410 mg of calcium oxide, corresponding to 7.3 millimoles or 14.6 milliequivalents, were added to the crude. Then the mixture was stirred at 100 ° C for 4 hours. The infrared examination showed no change in the intensity of the bands at 1708 and 1760 cm-1, which correspond to the dimeric and monomeric forms of the acids, compared to the untreated Bolobo 2/4 crude. 1 ml of water was added. After stirring at 100 ° C for 30 minutes, infrared examination showed that the bands at 1708 and 1760 cm-1 had disappeared, which shows the neutralization of the acids.

Example 5 (Comparative) This example is for comparison, ie to show that the alkali metal hydroxides do not require dilution with water to react with the acids of a dry crude. The reaction apparatus was the same as in Example 1. 100 g of the crude Gryphon, which has a total acid number of 4 mg KOH / g, was placed inside the reactor. 100 g of crude Gryphon contain 7.14 milliequivalents of acids. 286 mg of sodium hydroxide, corresponding to 7.14 milliequivalents were added. Then the mixture was stirred at 100dc for 3 hours. Infrared examination showed that the crests at 1708 and 1760 cm "" 1, which correspond to the dimeric and monomeric forms of the acids, had virtually disappeared, which indicated essentially complete neutralization.

Example 6 (Comparative) This example is for comparison, ie to show that alkali metal oxides do not require dilution with water to react with the acids of a dry crude. The reaction apparatus was the same as in Example 1. 100 g of the crude Gryphon was placed inside the reactor. Lugo added 221 mg of sodium oxide, corresponding to 3.57 millimoles or 7.14 milliequivalents. The mixture was heated to 100 ° C for 2 hours. Infrared examination showed that the crests at 1708 and 1760 cm-1, which correspond to the dimeric and monomeric forms of the acids, had virtually disappeared, indicating essentially complete neutralization.

Example 7 250 g of the crude oil having a high naphthenic acid content (total acid number = 8 mg of KOH per gram of oil) were placed in a corrosion test autoclave. The corrosion rate of the carbon steel in the crude oil was measured at a temperature of 316SC and gave a value of about 3.175 microns per year. The crude contained a calcium concentration of approximately 150 ppm. Then, to a fresh batch of 250 g of the same crude oil, the calcium naphthenate was added, so that the calcium content in the mixture changed to a value of 190 ppm. The corrosion rate of carbon steel was measured again in this mixture. As shown in Figure 1, the corrosion rate found was a factor of 2.5 less. The disproportionate decrease in the corrosion regime is attributed to the inhibition of corrosion by calcium naphthenates.

Example 8 The content of the naphthenic acid in the starting crude with high total acid numbers (TAN), described in Example 1, was completely neutralized by treatment with a stoichiometric amount of CaO, at a temperature of 99se. The virgin crude with high TAN was then mixed with the completely neutralized crude in weight ratios of 9: 1 and 7: 3, respectively. The corrosion rate of the carbon steel in the two mixtures was measured at a temperature of 316se. The results are shown as black bars in Figure 2. The corrosivity of the 9: 1 mixture (10% neutralized) is a factor of 6 lower when compared to the virgin crude and that of the 7: 3 mixture (30% neutralized) is a factor of 50 minor. Only neutralization had occurred without the synergistic inhibition of corrosion, a linear decrease in the rate of corrosion, proportional to the degree of neutralization, will have resulted, as illustrated by the bars shaded in Figure 2. The greatest decrease in the regimes Measured corrosion is further evidence of the inhibition of corrosion by metal carboxylates formed during neutralization.

Example 9 This is similar in concept to Example 8, except that a distillate fraction of 418-5212C, obtained from the crude Gryphon, was used as the starting material. Again, 316SC corrosion tests were performed with separate fractions of this sample neutralized at 10, 30 and 50% with CaO. Here, up to a reduction of 80% in the corrosion regime to a 50% neutralization was measured (black bars in Figure 3), with each measurement exceeding the hypothetical results (shadow bars) if the reduction of corrosion was proportional to the degree of neutralization.

Example 10 The reaction apparatus was a flask, equipped with a mechanical stirrer and reflux condenser, immersed in an oil bath. 50 g of the San Joaquim Valley crude, which has a neutralization number of 4.17 mg KOH / g, and 208 mg of finely ground potassium hydroxide, were placed in the flask. The temperature of the oil bath was increased to 100 se and held there for 5 hours, with vigorous stirring of the contents of the flask. After cooling, the solids were separated by centrifugation. The crude was analyzed and found to have a neutralization number of 1.09 KOH / g.

Example 11 The reaction apparatus was the same as that used in Example 10. 50 g of San Joaguim Valley crude and 150 mg of finely divided sodium hydroxide were placed inside the flask. The oil bath was brought to 100 ° C and kept there for 6 hours with intense shaking of the contents of the flask. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 1.02 mg KOH / g.

Example 12 The reaction apparatus was the same as that used in Example 10. 50 g of the San Joaquim Valley crude and 300 mg of finely divided sodium hydroxide were placed inside the flask. The oil bath was brought to 100 ° C and held for 8 hours with intense shaking of the contents of the flask. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 0.39 mg KOH / g.

Example 13 The reaction apparatus was the same as that used in Example 10. 50 g of the San Joaquim Valley crude and 156 mg of finely divided lithium hydroxide monohydrate were placed inside the flask. The oil bath was brought to 100 ° C and kept there for 6 hours with intense shaking of the contents of the flask. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 1.30 mg KOH / g.

Example 14 The reaction apparatus was the same as that described in Example 10. 50 g of San Joaquim Valley crude and 580 mg of barium hydroxide octahydrate were placed inside the flask. The oil bath was brought to 1002C and kept there for 6 hours with vigorous stirring of the contents of the flask. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 1.37 mg KOH / g, which corresponds to 31% of the original acidity still present. However, examination by infrared spectroscopy showed that the band at 1708 cm -1, which corresponds to the carboxyl group, had an intensity which was only 12% of that of the untreated crude.

Example 15 The reaction apparatus was a flask equipped with stirrer and reflux condenser, immersed in an oil bath. 50 g of the San Joaquim Valley crude, which has a neutralization number of 4.17 KOH / g and 0.566 g of barium oxide, was placed in the flask. The temperature of the oil bath was brought to 100 ° C and it was thus kept for 6 hours. After cooling, the solids were separated by centrifugation. The treated crude was analyzed and found to have a neutralization number of 0.24 mg KOH / g.

Example 16 The reaction apparatus was the same as in Example 10. 50 g of the same crude used in Example 15 and 0.23 g of sodium oxide were placed inside the flask. The oil bath was brought to 1008C and kept that way for 6 hours. After cooling, the solids were separated by centrifugation. The treated crude was analyzed and found to have an immeasurably low neutralization number.

Example 17 The reaction apparatus was the same as that described in Example 10. 50 g of the San Joaquim Valley crude and 490 mg of strontium hydroxide octahydrate were placed inside the flask. The oil bath was heated to 100 ° C and held for 8 hours while vigorously stirring the contents of the flask. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 3.20 mg KOH / g, which corresponds to 76% of the original acidity. However, examination by infrared spectroscopy showed that the band at 1708 cm -1, which corresponds to the carboxyl group, had an intensity which was only 36% of that of the untreated crude.

Example 18 The reaction apparatus was the same as that described in Example 10. 175 g of Bolobo 2/4 crude, which has a neutralization number of 8.2 mq KOH / g, and 3.9 g of barium oxide were placed inside of the flask. The temperature of the oil bath was brought to 100 ° C and the contents of the reactor were stirred for 8 hours. After cooling, the solids were separated by centrifugation. The oil had a neutralization number of 1.08 mg KOH / g.

Example 19 The reaction apparatus was the same as that described in Example 10. 50 g of the same crude used in this Example 10 and 1.04 g of calcium oxide were placed inside the reactor. The oil bath was brought to lOOsc and kept that way for 8 hours. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 3.4 mg KOH / g, which corresponds to 81% of the original acidity still present. However, examination by infrared spectroscopy showed that the band at 1708 cm -1, which corresponds to the carboxyl group, had an intensity which was only 30% of that of the untreated crude.

Example 20 The reaction apparatus was the same as that described in Example 10. 50 g of the same crude used in this Example 10 and 2.08 g of calcium oxide were placed inside the reactor. The oil bath was brought to 1002C and remained so for 6 hours. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 2.3 mg KOH / g, which corresponds to 55% of the original acidity still present. However, examination by infrared spectroscopy showed that the band at 1708 cm -1, which corresponds to the carboxyl group, had an intensity which was only 9% of that of the untreated crude.

Example 21 The reaction apparatus was the same as that described in Example 10. 50 g of Bolobo 2/4 crude, which has a neutralization number of 8.2 mg KOH / g, and 0.42 g of calcium oxide were placed inside of the reactor. The oil bath was brought to 100 ° C and remained so for 7 hours. After cooling, the solids were separated by centrifugation. The treated crude had a neutralization number of 5.9 mg KOH / g, which corresponds to 72% of the original acidity still present. However, examination by infrared spectroscopy showed that the band at 1708 cm -1, which corresponds to the carboxyl group, had virtually disappeared.

Example 22 The reaction apparatus was a glass column of 1 cm in internal diameter and 37 cm in height, filled with 100 g of barium oxide and heated to about 1202C. 96.2 g of Bolobo 2/4 crude, which has a neutralization number of 8.2 mg KOH / g, was passed through the column. The crude, thus treated, had a neutralization number of 1.7 mg KOH / g, which corresponds to 24% of the original acidity still present. However, examination by infrared spectroscopy showed that the band at 1708 cm -1, which corresponds to the carboxyl group, had an intensity which was only 5% of that of the untreated crude. EXAMPLE 23 The reaction apparatus was a 200 ml flask, equipped with stirrer and reflux condenser. 100 g of the North Sea Blend crude, which has a neutralization number of 2.1 mg KOH / g, 1 ml of water and 137 mg of Ca (OH) 2, was charged into the reactor and stirred at 100 ° C for 5 hours. Infrared examination showed that the band at 1708 cm "1, which corresponds to the carboxyl group, had virtually disappeared.Example 24 The reaction apparatus was a 100 ml flask, equipped with stirrer and reflux condenser 50 g of Bolobo 2 crude / 4, which has a neutralization number of 8.2 mg of KOH / g and 302 mg of magnesium oxide were placed inside the reactor.The mixture was stirred at 100 ° C for 7 hours.The infrared examination showed that the band at 1708 c "1 , which corresponds to the carboxyl group, had virtually disappeared.

Claims (28)

1. CLAIMS 1. A method for decreasing the corrosivity of a corrosive crude containing acid, this method comprises: contacting the starting corrosive crude oil, containing acid, with an effective amount of a naphthenate salt of a Group IIA metal , to produce a treated crude oil, which has a reduced correcivity.
2. 2. The method of claim 1, wherein the effective amount of the naphthenate salt is from greater than zero to 5: 1 moles per mole of acid functionality in the crude oil and the corresponding effective amount of the water is from greater than zero to 7. % by weight of the total corrosive crude oil, which contains acid.
3. 3. The method of claim 2, wherein the metal is selected from magnesium and calcium.
4. 4. The method of claim 2, wherein the effective amount of the naphthenate salt is from 0.025: 1 to less than 0.5: 1 moles, based on the acid content of the starting oil.
5. 5. The method of claim 2, wherein the effective amount of the naphthenate salt is from 1: 1 to 5: 1 moles, based on the acid content of the starting oil.
6. 6. The method of claim 2, wherein the effective amount of the water is at least 0.3% by weight, based on the total oil containing acid.
7. 7. The method of claim 2, wherein the effective amount of water is from 0.3 to 7% by weight, based on the total oil containing acid.
8. 8. The method of claim 1, wherein the crude oil is a total corrosive crude containing acid.
9. 9. The method of claim 1, wherein the crude oil is a corrosive crude fraction containing acid.
10. 10. The method of claim 1, wherein the crude oil is a fraction of the crude having a boiling point of more than 3432C.
11. 11. The method of claim 1, wherein the crude oil is a fraction of the crude having a boiling point of more than 565sc.
12. 12. The method of claim 1, wherein the crude oil is a vacuum gas oil.
13. 13. The method of claim 1, wherein the crude oil is a crude from the primary distillation.
14. 14. The method of claim 1, wherein the acid-containing crude oil is a corrosive crude oil containing a naphthenic acid.
15. 15. The method of claim 1, wherein the acid-containing corrosive crude oil has a neutralization number from 0.2 to 10 mg KOH / g.
16. 16. A method for reducing the corrosivity of a corrosive crude containing acid, this method comprises: mixing a starting corrosive crude, containing acid, with an effective amount of a second crude containing a metal naphthenate, in which the naphthenates Metals are selected from those of Group IA and IIA, to produce a final treated crude oil, which has a decreased corrosivity.
17. 17. The method of claim 16, wherein the metal naphthenate is selected from the calcium and magnesium naphthenates.
18. 18. The method of claim 16, wherein the metal naphthenate is from greater than zero to 10: 1 moles, based on the acid content of the crude starting oil, which contains acid.
19. 19. The method of claim 16, wherein the metal naphthenate is from 0.015 to 1: 1 moles of metal, based on the acid content of the crude starting oil containing acid.
20. 20. The method of claim 16, wherein the metal naphthenate is from 0.025 to 1: 1 moles of metal, based on the starting crude oil containing acid.
21. 21. The method of claim 16, wherein the raw crude oil and the second crude are total crude.
22. 22. The method of claim 16, wherein the raw crude oil and the second crude are fractions of the crude having comparable ranges of boiling point.
23. 23. The method of claim 16, wherein the raw crude oil and the second crude are fractions of the crude having a boiling point greater than 343 se.
24. 24. The method of claim 16, wherein the raw crude oil and the second crude are crude fractions having a boiling point greater than 565se.
25. 25. The method of claim 16, wherein the raw crude oil and the second crude oil are crude from a primary distillation.
26. 26. The method of claim 16, wherein the crude oil containing acid is a corrosive crude oil containing a naphthenic acid. The method of claim 16, wherein the starting corrosive crude oil, which contains acid, has a neutralization number from 0.2 to 10 mg KOH / g. The method of claim 1 or 16, wherein the metal naphthenate is a complete salt or a half-salt.