Patent Application
20120255886
This application claims the benefit under 35 U.S.C. §119 of Mexican Patent Application No. MX/a/2011/003848, filed Apr. 11, 2011, which is hereby incorporated by reference in its entirety.
This invention is related to dehydration and desalting of crude median, heavy and extra heavy oils, using ionic liquids (IL's) individually and/or formulation.
Crude oil produced from wells located offshore and in inland areas, is emulsified with different proportions of water. The percentage of water also varies greatly during the production history of wells. Because of their molecular characteristics, oil and water are immiscible, but when oil is produced, it is inevitable the simultaneous production of water. Once production begins, both oil and water are transported to storage tanks through pipelines, power applied it generates turbulence which promotes the mixing of both phases leading to different emulsion of water/oil, oil/water, water/oil/water and oil/water/oil, such emulsions can become very stable and are favored by emulsifying compounds (asphaltenes, carboxylic acids, resins and clays) naturally present in crude oil. The stability emulsions depend largely on the composition of crude oil (Hellberg P E et al 2007).
The emulsified water in oil, containing carbonates and sulphates of sodium, magnesium and calcium, which if not are removed, can cause various problems in subsequent refining processes. The proportion of water in oil has a ceiling of 0.5% and a salt content of less than 50 mg/L, so that the first unit operation to be performed in the petroleum refining, is the removal of water and therefore of the salts that it contains.
Initially crude desalting was done as a preventive measure to reduce corrosion, but in recent years desalination technology has become more important, it helps also to protect the catalysts used in later stages of the refining process. (Xu X et al 2006).
Therefore, from the operational point of view and mainly economic, it is imperative and important to separate water from oil, as completely and as quickly as possible in the same production site. To achieve this goal batteries have been used in for separation, physical and chemical methods, independently or sequentially. (Hellberg P E et al 2007).
The chemical removal of water consists of the addition of small amounts of demulsifiers (1 to 1000 ppm) to crude oil stored in tanks of separation, just before being pumped, to break the emulsion water in oil (Spinelli L S et al 2007).
The demulsifiers most often used today in the oil industry are resins of the type alkyl-formaldehyde, copolymers of propylene polyoxide-polyethylene oxide, alkoxylated amines, alkoxylated epoxy resins, dissolved in one or more solvents such as xylenes, toluene, gasoline and short chain alcohols. Its mechanism of action promotes the coalescence of small droplets of water in large droplets, which then flocculate thus leading to the separation of both phases. It has also been established that the role of a good demulsifier is to alter the rheological properties of interfacial layer and destabilize the oil layer endogenous emulsifier. Usually commercial demulsifiers are a mixture of several components with different polymer structures, as well as a wide range of molecular weights. (Al-Sabagh A M et al 2002).
As important examples in the literature which mention the use of demulsifiers to break the emulsion water in oil, in the oil industry may be mentioned the following international references:
Adducts (esters and amides) of oleic acid-maleic anhydride have been used (1) in demulsification of crude oil (API=41) which water content varies from
10% to 30%: obtaining water removals near 100% at concentrations of 200 ppm at temperatures above 40° C. (Al-Sabagh A M et al 2002). International Patent WO 2009/097061 A1 describes the use of different demulsifiers such as those shown below (2):
R—O—(XO)a-(YO)b-(ZO)c-H (I)
R2-O-Jp-O—(XO)a-H (II)
R—O—(CH2-CH(CH2(BO)d)-O)a-(CH2-CH(CH3)-O)b-(CH2-CH(CH2(BO)d)-O)c-H (III)
(2) Demulsifiers of the international patent application WO 2009/097061 A1
where R can be H, alkyl-(C1-C30)-phenol, dialkyl-(C1-C30)-phenol, alkoxylated polyamine and/or an alcohol or polyol; X, Y, Z and B represent alkyl residues of methylene, ethylene, propylene, 3-hydroxypropylene, butylene, phenylene, and mixtures thereof; a, b, c and d are independent numbers representing from 1 to 500 units of ethylene oxide, oxide of 3-hydroxy-propylene and mixtures of them, R2 is a linear or branched alkyl radical, saturated or unsaturated, J is a radical oligocosile, so that the demulsifiers containing at least 70% by weight of ethylene oxide and/or oxide of 3-hydroxy propylene. The above mentioned demulsifiers were also modified with: alcohols, aliphatic and aromatic anhydrides, alkyl and benzyl halides, carboxylic acids and isocyanates among some other functional groups, including polymerizable monomers; these modified demulsifiers were applied in a range of concentrations ranging from 1 to 1000 ppm and temperature from 60° C. to 150° C. in crudes which API gravity hovers around 20 and containing connate water or in crude oil to which was added wash water. (Patel N et al 2009).
WO 2009/023724 discloses a set of formulations composed of one or more anionic surfactants, and one or more non ionic surfactants. The anionic surfactants are comprised of anionic alkylsulfosuccinates, alkylphosphonic acids and their salts and any combinations of them; the non ionic surfactants are selected from the group of copolymers of polyethylene oxide/polypropylene oxide, ethoxylated fatty acid of polyethylene glycol, modified alkanolamides and alkoxylated terpenes (
WO 2006/116175 discloses use of a demulsifier composition prepared by the reaction of alkyl phenol resins, formaldehyde or one or more polyalkyleneglycols or mixing them, with various phosphorus compounds selected from the group that comprises phosphorus oxychloride, phosphorus pentoxide and phosphoric acid in a molar ratio from 0.001 to 1.0. The addition of the demulsifier composition was held from 50 to 500 ppm in crude oils with API gravity equal to 15 (Myers C et al 2006).
U.S. Pat. No. 5,609,794 discloses the use of an adduct of polyalkylene glycol and ethylene oxide, which is esterified with an anhydride to form the diester, which is then reacted with vinyl monomers and so on, to form different esters: the formulations were applied in a temperature range from 7° C. up 80° C. in concentrations ranging from 10 to 1500 ppm and were applied to oil (unspecified) and different currents (jet fuel, gasoline, lubricating oils and others). It is mentioned that the separated water reaches 40% in volume within several minutes, without specifying how many (Taylor G N 1997).
On the other hand, ionic liquids (IL's) have been used in various applications in the pharmaceutical, petrochemical and chemical industries. The IL's are materials which are ionic liquid phase in the temperature range between 0 and 100° C., and because they are composed mainly of ions. The IL's have low vapor pressures, thereby reducing the risk of air pollution (Collins I R et al 2006).
The IL's have been applied in the oil industry for different purposes, as described below:
IL's the type octylsulfate butyl-methyl-imidazolium and ethylsulfate ethyl-methyl-imidazolium have desulfurized current refineries as well diesel and gasoline from FCC. The yields obtained vary between 95 and 99% when applied to synthetic diesel, using the IL's before mentioned in 5 successive extractions. Their mode of action involves the selective extraction of aromatic compounds such as dibenzothiophene, which is very difficult to remove in the process HDS (hydrodesulfurization), including the authors propose this methodology as a viable alternative to HDS process (Esser J et al 2004).
The IL's also have been used as lubricants (4) in aircraft, in addition withstand temperatures above 415° C. (Canter N. 2007).
WO 2008/124042 discloses the use of IL's type quaternary ammonium, phosphonium, pyridinium, imidazolium, tetrazolium and triazolium salts with a wide variety of anions as sulfate, phosphate, alkylsulfonate, alkylphosphate, chloroaluminates among others, to selectively extract resins, polyaromatics and heterocyclic compounds with high molecular weight from bitumen, vacuum residues and heavy oils, in a ratio IL: crude oil (1:5) at temperature ranges between 50° C. and 225° C., to increase API gravity of these currents (Siskin M, et al 2008).
The IL's also have been used to selectively extract diesel basic nitrides, e.g. chloroaluminate of 1-butyl-3-methyl-imidazolium extracted with 97% efficiency, using a weight ratio of IL's/diesel=0.03 at a temperature of 50° C. for 3 minutes (Peng G, et al 2005).
The simultaneous application of IL's and microwave energy have been used to promote the breakdown of water emulsions in crude oil, it considers the use of microwaves as a heating source that accelerates and increases the efficiency of the demulsification, this treatment was applied to crude oils with API gravities between 21 and 30 (Rojo T 2009, Guzmán-Lucero D J et al 2010).
Considering the operating conditions of the management of oil and its value in international markets, is of paramount importance to break the water/oil emulsions to remove the water dispersed while the crude oil desalting. The water removal means to produce oil with the required quality for export and/or refining, it also means reducing corrosion in oil installations and the poisoning of the catalysts used during processing.
Considering the above, we proceeded to make demulsifiers formulations based IL's, for treatment of medium, heavy and extra heavy crude oil, since none of the references mentioned above claim the employment of formulations containing them, with similar or better efficiencies demulsifiers and dehydrating over medium, heavy and extra heavy crude oils, which API gravities are between 8 and 20.
A brief description of the drawings contained in the present invention:
The present invention relates to the application of different families of IL's and their formulations in the demulsification of median, heavy and extra-heavy crude oils which API gravities are within the range of 8 to 30.
The invention is directed to the use of ionic liquids dissolved in solvents having a boiling point in the range from 35° C. to 200° C., preferably dichloromethane, chloroform, methanol, isopropanol, ethanol, benzene, toluene and xylenes, individually or in mixtures of them; when they are used in concentrations from 50 ppm to 2000 ppm, preferably from 600 ppm until 1750 ppm, even more preferably from 750 ppm to 1500 ppm, to break water in oil emulsions and simultaneously desalt crude oils having and API gravity between 30 and 8°.
The invention is directed to the use of formulations consisting of ionic liquids dissolved in solvents having a boiling point in the range from 35° C. to 200° C., preferably dichloromethane, chloroform, methanol, isopropanol, ethanol, benzene, toluene and xylenes, individually or in mixtures of them; when they are used at concentrations of 50 ppm until 5000 ppm, preferably from 600 ppm to 1750 ppm, even more preferably from 750 ppm to 1500 ppm; to break water in oil emulsions and simultaneously desalt crude oils having an API gravity between 20 and 8°.
The IL's whose use as demulsifiers and dehydrating claimed in this invention were synthesized, purified and characterized by spectroscopic techniques such as infrared, NMR (1H and 13C) and mass spectrometry, according to the methods described in the literature: Martinez R, et al (2010), Flores E A, et al (2009), Tao G H, et al (2005); Himmler S et al (2006).
The IL's used in the present invention have general formula C+ A−, where C+ is an organic cation represented by 1,5-dicarboxy-pentan-2-ammonium, imidazolium, pyridinium, isoquinolinium, ammonium and carboxymethane-ammonium; and A− is an organic anion, as given in Table 1.
Following is described the characterization of the evaluated crude oils in the present invention with the IL's described above:
Evaluation of IL's independently and formulated, such as demulsifier and desalting agents in median, heavy and extra-heavy crude oils.
Different concentrated solutions of each of the IL's were prepared, from 5 to 40% by weight, using solvents with boiling point falls in the range of 35 to 200° C., preferably dichloromethane, methanol, ethanol, isopropanol, chloroform, benzene, toluene, xylene, turbosine, naphtha, individually or in mixtures of them, so they added small volumes of the dissolution and was avoided that the effect of the solvent influenced in the breakdown of the emulsion. The IL's were evaluated in concentrations falling within the range of 100 to 2000 ppm.
The IL's were evaluated simultaneously by way of comparison with commercial formulations of the base type of propylene oxide and ethylene oxide, as demulsifier and desalting agents, Table 3 describes the determination of molecular weights (GPC) of the commercial copolymers.
The evaluated procedure is described below: the number of oblong bottles provided with insert and lid was indicated by the number of compounds to evaluate, over an additional which corresponds to the crude oil without additive; in each one of them was added crude oil to the 100 mL mark. All the bottles were placed in a bath of water at a controlled temperature in 80° C. for 20 minutes, at the end of that time was added the aliquot part of the dissolution of the IL's (individual or formulations) and formulations of commercial copolymers mentioned above; all the bottles were agitated during 3 minutes at a rate of 2 shots per second. After being purged were placed new account in the temperature-controlled bath and the breaking of emulsion water in oil was successively read in the following way: every 5 minutes during the first 60 minutes, every 10 minutes during the second hour, and finally every hour until the end of the test. All the IL's a matter of this invention and commercial formulations were evaluated at different including concentrations in the range 100 to 2000 ppm.
By way of demonstration, which does not imply any limitation, are shown in the following figures, the graphical results of the evaluation described above, for different concentrations of both individual and formulated IL's.
In the
In Table 4, the values for the efficiency in the dehydrated and desalted after of the treatment with IL's are shown (to see
For the IL-06 the values of desalted are very similar although the greater proportion of removed water was obtained with the concentration of 500 ppm. On the other hand, the IL-21 obtained the greater water removal with the concentrations of 1500 and 2000 ppm, however the greater proportion of desalted was obtained with the concentration of 1500 ppm, being also this concentration the one that desalted with greater effectiveness to the Mayan crude.
In addition, in
With the purpose that the investigation developed in this invention is even more useful to the national system of refineries, we proceeded to evaluate the IL's in crude even heavier (smaller API gravity). For this purpose, it is prepared a crude denominated M+T (API=17.1) starting from the combination of 6 volumes of Mayan crude oil (API=19.1) and 1 volume of Tekel crude oil (API=14.84). The evaluation also included the comparison with two commercial products, one of them is a triblock copolymer of polypropylene oxide—polyethylene oxide of the Company Z (Z-1) (Mn=2900 and I=1.07) and the other one is a formulation property of the IMP (RHS-5). The results are shown in the following graphics.
The IL's 6, 16, 17 and 21 break with greater efficiency the emulsion water-oil when compares with IMP formulation and the commercial copolymer; the IL-21 obtained the major efficiency (90%) to the 240 minutes. These results are shown in the
Next the values obtained in the desalted stage are compared with the treatment realized by the IL's and with commercial products.
In
So far it is observed that is greater drying efficiency and therefore the efficiency of desalination of IL's compared to commercial copolymer and the formulation of IMP, which consists of breakers, coalescing and clarifiers agents of the emulsion
Continuing the ILs application, they were evaluated in a heavier crude oil (API=9.2); results are shown in the following graphs:
The water removal efficiency of IL's 16, 17, and 21, at a concentration of 1500 ppm is reported in
A comparative study of the dehydrating and desalting efficiencies of the ionic liquids 16, 17 and 21 and some commercial copolymers of X and Z companies (x and Z copolymers respectively).
It may be easily observed in
A similar behavior is observed in
In the Table 6 are summarized the percentages of desalting and dewatering of IL's 16, 17 and 21, compared to those of commercial copolymers provided by Z and X companies; it is clear that the performance of the IL's are better in both aspects.
Different formulations were obtained from combinations of IL's 16, 17 and 21 at different compositions; the performance of these formulations is reported in
In
It is also important to remark that formulations, which performance is reported in
Finally, it may be observed in Table 7 that the dehydrating and desalting efficiencies of IL's are greater than those of formulations prepared with commercial products from X and Z companies.
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| Number | Date | Country | Kind |
|---|---|---|---|
| MX/A/2011/003848 | Apr 2011 | MX | national |
