DE69818619T2 - Process for reducing the acidity of crude oil and fractions - Google Patents

Description

AREA OF INVENTION

The present invention relates to a process for reducing the acidity and corrosiveness of crude oils and Crude oil fractions that contain mineral oil acids.

BACKGROUND THE INVENTION

Many high crude mineral oil products of organic acid, like naphthenic acids containing complete crude oils are opposite used for the extraction, transport and processing of the crude oil Material such as piping and transport lines corrosive.

Efforts to minimize the Corrosion from naphthenic acid concluded a number of approaches on. Examples of such technologies include the use of oil-soluble ones Reaction products of an alkylidene diol and a polyalkene polyamine (US Pat. No. 4,647,366), as well as the treatment of a liquid Hydrocarbon with dilute aqueous alkaline Solution, especially thinner aqueous NaOH or KOH (US-A-4,199,440). US-A-4,199,440 noted however, that the use of aqueous NaOH or KOH solutions, the higher Contain concentrations of base with which oil form emulsions, whereby only dilute watery, basic solutions can be used. US-A-4,300,995 discloses the treatment of carbonaceous or carbonaceous materials, especially coal and their Products such as heavy oils, Vacuum gas oils and mineral oil residues acidic functionalities with a quaternary Base such as tetramethylammonium hydroxide in a liquid (alcohol or water). Other processes that use bases such as aqueous alkali hydroxide solutions include those in Kalichevsky and Kobe, Petroleum Refining With Chemicals, (1956), Ch. 4, and US-A-3,806,437, US-A-3,847,774, US-A-4,033,860, US-A-4,199,440 and US-A-5,011,579, DE-A-2 001 054 and DE-A-2 511 182, CA-A-1,067,096. JP-A-59-179588, RO-A-104,758 and CN-A-1,071,189 of the disclosed methods. WO-A-97/08270, WO-A-97/08271 and WO-A-97/08275, published March 6, 1997, all disclose treatment with overbased surfactants and group IA and IIA oxides and hydroxides to reduce acidity and / or corrosion. Certain Treatments were made on mineral oil distillates and hydrocarbon oils performed (e.g. B. with lime, melted NaOH or KOH, certain highly porous calcined Salts of carboxylic acids, those on carrier media were suspended). full crude oils were not treated.

US-A-2,795,532 and US-A-2,770,580 (Honeycutt) disclose procedures that treat "heavy mineral oil fractions" or "mineral oil vapors", by "quenched Vapors "with" liquid alkaline Material "contacted which contains, among other things, alkali metal oxides and "liquid oil" under Use a mixture of molten NaOH and KOH as that preferred treatment agents and "other alkaline materials, e.g. B. Lime, which is also used in smaller quantities ". The treatment of total crude or fractions thereof boiling at 1050 + ° F (565 + ° C) is not disclosed; only vapors or condensed vapors the 1050 ° F (565 ° C) fractions, d. H. Fractions under the conditions disclosed in US-A-2,795,532 are vaporizable are treated. There are synthetic naphthenic acids through all crude oil fractions distributed (many of which are not vaporizable) and, because crude oils are strong in its naphthenic acid content one cannot differentiate from US-A-2,795,532 that one is able to handle a wide cross section of crude oils with a Variety of boiling points to treat successfully or other bases to use as NaOH and KOH.

GB-A-4 967 779 discloses a Process for reducing acidity of an acidic crude Contacting the oil in the vapor phase at a temperature above 300 ° C with a higher catalyst porosity and great catalytic surface, preferably selected made of lithium carbonate and calcium.

US-A-2,068,979 discloses one Process for preventing corrosion in a mineral oil by to make calcium naphthenate to mineral oil gives them reaction and strong free acids like hydrochloric acid and sulfuric intercepted to prevent corrosion in the distillation units to prevent. The patent does not disclose claims regarding naphthenic acids that could be formed if the strong acids be converted to salts. Patents include the addition or Formation of calcium carbonate (Cheng et al., US-A-4,164,472) or Magnesium oxide dispersions (Cheng et al., US-A-4,1b3,728 and US-A-4,179,383 and US-A-4,226,739) as corrosion inhibitors in fuel products and lubricating oil products disclosed, but not in whole oils or topped crude oils. Reported similarly Mustafaev et al. (Sb. Tr., Azerb. Inst. Neft. Khim. (1971) 64-6) on the improved lubricity and anti-corrosive properties of calcium, barium and zinc hydroxide additives in lubricating oils. calcium hydroxide (Kessick, CA-A-1,249,760) was used to separate water from heavy crude oil waste.

There is a continuing need to develop processes to reduce the acidity and corrosiveness of whole crude oils and fractions thereof, especially residues and others 650 + ° F (343 + ° C) fractions. Applicants' invention addresses these needs.

SUMMARY THE INVENTION

The present invention provides a method to reduce the acidity and corrosiveness of a Acid-containing, corrosive crude oil, where an initial Acid-containing, corrosive crude oil with an effective amount of at least one manganese oxide for manufacture a treated crude oil with reduced acidity and corrosiveness is contacted. The treated crude oil contains naphthenate and ketone derivatives of naphthenic acids. water can in the crude be present or added, or may be absent.

The present invention may suitably be used the elements disclosed include, consist of, or essentially consist of and may be in the absence of an undisclosed Element become.

DETAILED DESCRIPTION OF THE INVENTION

Some whole crude oils contain organic acids such as carboxylic acids, that contribute to the corrosion or contamination of refinery plants. These organic acids fall in general in the category of naphthen and other organic acids. Is naphthenic acid a generic expression used to identify a mixture of organic acids is used, which is present in mineral oil stocks are. naphthenic can create corrosion at temperatures in the range of about 65 ° C (150 ° F) to 420 ° C (790 ° F). Are naphthenic acids in a wide range of boiling points (i.e. fractions) in acid-containing ones crude oils distributed. The present invention provides a method for broad Treatment of such acids, and especially from heavier (higher boiling point) and liquid fractions, in which these acids are often concentrated. The naphthenic acids to be removed can either alone or in combination with other organic acids such as Phenols may be present.

Whole crude oils are very complex mixtures, in which a large Number of competing reactions can occur. Thus, the potential for being successful Apply a specific treatment or procedure not necessarily predictable from the success of other treatments or procedure. They unexpectedly find this one Acid neutralization reactions described in the invention instead, although the acid compared to the big one Amount of raw material and other reactive materials typically present Species diluted is.

The method according to the invention can be used in methods in which the prevention or control of liquid phase corrosion, e.g. B. of metal surfaces is desired. More generally, the present invention can be used in applications where a decrease in acidity would be beneficial, typically evidenced by a decrease in the neutralization number of the crude acid oil or a decrease in the intensity of the carboxyl band in the infrared spectrum at about 1708 cm ^{-1 of} the treated (neutralized) Crude oil, and where the formation of oil-aqueous emulsion and large volumes of solvent is not desirable. The appearance of a band at 1600 cm ^-1 indicates the formation of carboxylate groups and at 1715 cm ^-1 of keto groups from the carboxylic acid groups. The treated crude oil thus contains naphthenate and, preferably, ketone derivatives of the organic acids. The present invention also provides a process for controlling emulsion formation in acidic crude oils which treats a major contributing component of such emulsions, naphthenic and similar organic acids, and alleviates the subsequent handling and processing problems.

The concentration of acid in the crude oils is typically indicated by an acid neutralization number or total acid number (TAN), which indicates the number of mg in KOH required to neutralize the acid of 1 g of oil. It can be determined according to ASTM D-664. Typically, the decrease in acidity can be determined by a decrease in the neutralization number or the intensity of the carboxyl band in the infrared spectrum at about 1708 cm ^-1 . The appearance of a band at 1600 cm ^-1 indicates the formation of a carboxylate salt and at 1715 cm ^-1 indicates the formation of a keto group from the carboxylic acid groups. Crude oils with total acid numbers of about 1.0 mg KOH / g and lower indicate moderate or low corrosivity (crude oils with a total acid number of 0.2 or less are generally considered to be low corrosive). Crude oils with total acid numbers greater than 1.5 are corrosive. IR analysis is particularly useful in cases where a decrease in the neutralization number is not apparent in base treatments, such as occurs when treating bases that are weaker than KOH.

The crude oils used can contain any naphthenic acid crude oils be liquid at temperatures or liquefiable in which the present invention is carried out. Typically, the crude oils a TAN of 0.2 to 10 mg KOH / g. As used here, it means Expression complete crude oils, unrefined and undistilled crude oils.

The contacting is at a temperature between 120 and 300 ° C carried out, narrower limits suitably from about 150 ° C to 300 ° C, preferably 200 ° C to 300 ° C.

According to the invention, corrosive acidic crude oils, i.e. H. those that are naphthenic acids alone or in combination with other organic acids such as phenols included, treated.

The acidic crude oils are preferably whole crude oils. Indeed can also fractions of total oils like topped crude oils and other high boiling point fractions are treated. It become crude oils or crude oil fractions with a boiling point of 650 + ° F (343 + ° C), preferably 1050 + ° F (565 + ° C) treated.

In the present invention, the crude oil is treated with an effective amount of at least one manganese oxide at a temperature sufficient to provide a treated crude oil with reduced acidity. The oxides include MnO, Mn ₂ O ₃ and Mn ₃ O ₄ . Treatment can be effective, in the presence or absence of water. If present, water can be added or occur naturally.

The response times depend on the temperature and the type of crude oil to be treated, its acidity off, can however, typically from less than about 1 hour to about 20 Hours to make a product with reduced corrosiveness and decreased acidity to deliver. The treated crude oil contains Naphthenate salts of the corresponding one used in the treatment Oxide and contains desirably Ketone derivatives of naphthenic acids.

The material is added as a solid what also a solid-in-liquid slurry, solid-in-water or solid-in-organic acid slurry or aqueous Includes suspension. The material becomes the crude oil containing acids in a molar ratio given that to produce a neutralized or partially neutralized (i.e. non-corrosive) crude oil is effective; the neutralization can take place in whole or in part, as required. There are relationships from oxide to total acid from 0.01: 1 mol to 5: 1, preferably 0.25: 1 to 2: 1.

The formation of a crude oil-aqueous (i.e. either water-in-oil or oil-in-water) emulsion tends to disturbance the efficient separation of the crude oil and water phases and thus the recovery of the treated crude oil. emulsification is undesirable and a specific problem encountered during the treatment of naphthenic acid-containing crude oils with watery Bases occurs. The method according to the invention can be essentially absent of emulsion formation. So is an additional one Advantage of treatment for the absence or essentially absence of emulsion formation.

The oxides can be purchased commercially or at Be made using known methods. In solid form can they are in the form of a powder or a composite, particles be of a certain size or on a heat-resistant (ceramic) Matrix supported his. Certain solids typically occur as crystals of Hydrate on.

The present invention can be found in Terms of the following, non-limiting. Examples shown become.

example 1

The reaction device was an autoclave with a capacity of 250 ml.

100 g of Bolobo 2/4 crude oil with a total acid number of 7.4 mg KOH / g, determined by infrared spectroscopy, were placed in the autoclave. 0.53 g of manganese (II) oxide was added, then the autoclave was closed, heated to 300 ° C. and then kept under stirring for 24 hours. After cooling, the oil was examined by infrared spectroscopy. A band at about 1600 cm ^-1 , partially overlaid by a band already present in untreated Bolobo 2/4, indicated the formation of a carboxylate, probably manganese (II) naphthenate. An intense band at 1708 cm ^-1 that was present in untreated Bolobo 2/4 and was assigned carboxyl groups was not present in the treated sample. A weak band at about 1715 cm ^-1 that was present in the treated sample did not change when the sample was treated with triethylamine, indicating the presence of a keto group rather than a carboxyl group.

Example 2

Example 1 was without manganese (II) oxide repeated.

Investigations of the reaction product by infrared spectroscopy showed that the band at 1708 cm ^-1 , which was assigned carboxyl groups, was somewhat lower than in untreated Bolobo 2/4. Addition of triethylamine completely eliminated the band at 1708 cm ^-1 , showing that it is due to unchanged carboxyl groups.

Example 3

Experiment 1 was repeated, the reaction time at 300 ° C. being reduced from 24 to 6 hours. The infrared spectrum of the product was similar to that of Example 1. The intense band at 1708 cm ^-1 that was present in existing bolobo had almost completely disappeared. A much smaller band, which was present at about 1715 cm ^-1 in the treated sample, did not change after the addition of triethylamine, indicating the more likely presence of keto groups as carboxyl groups.

A band at about 1600 cm ^-1 , partially overlaid by a band present in untreated Bolobo 2/4, indicated the formation of carboxylate, probably manganese (II) naphthenate.

Example 4

The treated oil from Example 1 was distilled to 566 ° C (1050 ° F). The distillate was found to have less than 0.08 ppm manganese. The remaining 36 g residue, all containing manganese (II) oxide, was used to treat another 100 g batch of Bolobo 2/4 crude oil. As in Example 1, the reaction was carried out in a closed autoclave at 300 ° C. for 24 hours. After cooling, the oil was examined by infrared spectroscopy. A band at about 1600 cm ^-1 , partially overlaid by a band that was already present in the spectrum of untreated Bolobo 2/4, indicated the formation of carboxylate, probably manganese (II) naphthenate.

A band at 1715 cm ^-1 attributable to carboxyl groups was significantly less intense than in the untreated Bolobo 2/4. Treatment of the sample with triethylamine only partially removed the peak at 1715 cm ^-1 , suggesting the presence of keto groups.

Example 5

The reactor was the same autoclave as described in Example 1. 100 g of Gryphon crude oil with an acid number of 4.2 mg KOH / g and 296 mg Mn ₂ O ₃ were added to the autoclave and heated at 300 ° C. for 24 hours. After cooling, the sample was centrifuged to separate the solids, then the oil was examined by infrared. A peak at 1715 cm ^-1 was about 20% as intense as the 1708 cm ^-1 peak that was present in untreated Gryphon and is due to carboxyl groups. Treatment of the sample with triethylamine produced no change in the 1715 cm ^-1 peak, suggesting that it was due to keto groups rather than residual carboxyl groups.

Example 6

The reactor was as described in Example 1. except that an uncooled condenser was connected to the autoclave, which allowed air to enter the reactor and light ends to exit. 100 g of Gryphon crude oil with an acid number of 4.2 mg KOH / g and 296 mg Mn ₂ O ₃ were added to the autoclave and heated at 300 ° C. for 24 hours. After cooling, the sample was centrifuged to separate the solids, then the oil was examined by infrared spectroscopy. A peak at 1715 cm ^-1 was about 20% as intense as the carboxyl groups at 1708 cm ^{-1 of} the starting oil. The peak at 1715 cm ^-1 is attributed to keto groups.

Claims (8)

Process for reducing the acidity of an acid crude oil or an acidic crude oil fraction with a boiling point of 343 + ° C (650 + ° F) where the sour crude or a fraction thereof with 0.01 to 5 mol based on the acidity of the starting crude or the fraction thereof, of at least one manganese oxide in one Temperature in the range of 120 to 300 ° C is contacted. The method of claim 1, wherein the manganese oxide is selected from one or more of MnO, Mn ₂ O ₃ and Mn ₃ O ₄ . The method of claim 1 or 2, wherein the amount of manganese oxide used is 0.25 to 2 mol. Method according to one of the preceding claims, which the manganese oxide as a solid or solid-in-liquid emulsion is used. Method according to one of the preceding claims, which is the starting crude a boiling point of 565 + ° C (1050 + ° F) having. Method according to one of the preceding claims, which is the starting crude or fraction thereof has a neutralization number of 0.2 to 10 mg KOH / g having. Method according to one of the preceding claims, which the contacting is carried out in the range of 200 to 300 ° C. Use of at least one manganese oxide as acidity reducing Means according to one of the Expectations 1 to 6.