Synergistic formulations of functionalized copolymers and ionic liquids for dehydrated and desalted of medium, heavy and extra heavy crude oils

Abstract

The present invention is related to formulations including one or more block copolymers with low polydispersity and bifunctionalized with amines, and an ionic liquid. A method of demulsifying, dehydrating, and desalting crude oils having API gravity ranging between 8 to 30 admixes the formulation with the crude oil in an amount effective to demulsify, dehydrate and/or desalt the crude oils.

Claims

1. A method of demulsifying, dehydrating and desalting light, medium, heavy and extra-heavy crude oils having an API gravity of 8 to 30 API comprising the step of combining the crude oil and a formulation in an amount of 5 to 3000 ppm based on the amount of crude oil effective for demulsifying the crude oil and forming a mixture, said formulation comprising a mixture of (a) a poly(ethyleneoxide) poly(propyleneoxide) poly(ethyleneoxide) copolymer having a molecular weight of 400 to 4400 Daltons and a polydispersity of 1.02 to 1.5 and bifunctionalized with an amine, and a synergistic amount of (b) an ionic liquid having a cation selected from the group consisting of 1,5-dicarboxy-pentane-2-ammonium, pyridinium, isoquinolinium, imidazolium, ammonium and ammonium carboxymethane, and an anion selected from the group consisting of R.sub.5COO.sup., Cl.sup., Br.sup., [BF.sub.4].sup., [PF.sub.6].sup., [SbF.sub.6].sup., [R.sub.6SO.sub.4].sup., [OTs].sup., [OMs].sup.31 , where R.sub.5 is an alkyl, cycloalkyl, benzyl, alkenyl, aromatic, or allyl-functionalized chain having 1 and 18 carbon atoms; and R.sub.6 is methyl or ethyl, and mixing the resulting mixture for a time sufficient to demulsify, dehydrate and desalt the crude oil.

2. The method of claim 1, wherein said amine is selected from the group consisting of a C-5 or C-6 heterocyclic amine having an oxygen or nitrogen heteroatom, and an acyclic group substituted with an aliphatic or aromatic group.

3. The method of claim 1, wherein said block copolymer and ionic liquid are present in an amount of 1 to 50% by weight based on the total weight of the formulation and where said formulation further contains a solvent having a boiling point of 30 C. to 200 C.

4. The method of claim 3, wherein said solvent is selected from the group consisting of dichloromethane, chloroform, benzene, toluene, xylenes, jet fuel, naphtha and linear and branched C.sub.1 to C.sub.8 alcohols.

5. The method of claim 1, wherein said poly(ethyleneoxide) poly(propyleneoxide) poly(ethyleneoxide) copolymer and said ionic liquid are mixed with said crude oil in an amount of 50 to 1500 ppm based on the amount of the crude oil.

6. The method of claim 1, wherein said poly(ethyleneoxide) poly(propyleneoxide) poly(ethyleneoxide) copolymer and said ionic liquid are mixed with said crude oil in an amount of 100 to 1000 ppm based on the amount of the crude oil.

7. The method of claim 1, wherein said copolymer has a molecular weight of 1000-4000.

8. The method of claim 1, wherein said copolymer has a molecular weight of 400-800.

9. The method of claim 1, wherein said copolymer and said ionic liquid are present in substantially equal amounts in said formulation.

10. The method of claim 1, wherein said copolymer and ionic liquid are added in an amount of 50-1500 ppm.

11. The method of claim 1, wherein said copolymer and ionic liquid are added in an amount of 200-500 ppm.

12. A method of desalting light, medium, heavy and extra-heavy crude oils having an API gravity of 8 to 30 API comprising the step of combining a formulation to crude oil in need of desalting in an amount of 5 to 3000 ppm based on the amount of crude oil effective for desalting the crude oil and forming a mixture, said formulation comprising a mixture of (a) a poly(ethyleneoxide) poly(propyleneoxide) poly(ethyleneoxide) copolymer having a molecular weight of 400 to 4400 Daltons and a polydispersity of 1.02 to 1.5 and bifunctionalized with an amine, and a synergistic amount of (b) an ionic liquid having a cation selected from the group consisting of 1,5-dicarb oxy-p entane-2-ammonium, pyridinium, isoquinolinium, imidazolium, ammonium and ammonium carboxymethane, and an anion selected from the group consisting of R.sub.5COO.sup., Cl.sup., Br.sup., [BF.sub.4].sup., [PF.sub.6].sup., [SbF.sub.6].sup., [R.sub.6SO.sub.4].sup., [OTs].sup., [OMs].sup., where R.sub.5 is an alkyl, cycloalkyl, benzyl, alkenyl, aromatic, or allyl-functionalized chain having 1 and 18 carbon atoms; and R.sub.6 is methyl or ethyl, and mixing the resulting mixture for a time sufficient to desalt the crude oil.

13. The method of claim 12, wherein said copolymer has a molecular weight of 1000-4000.

14. The method of claim 12, wherein said copolymer has a molecular weight of 400-800.

15. The method of claim 12, wherein said copolymer and said ionic liquid are present in substantially equal amounts in said formulation.

16. The method of claim 12, wherein said copolymer and ionic liquid are added in an amount of 50-1500 ppm.

17. The method of claim 12, wherein said copolymer and ionic liquid are added in an amount of 200-500 ppm.

18. A method of demulsifying, dehydrating and desalting light, medium, heavy and extra-heavy crude oils having an API gravity of 8 to 30 API comprising the step of combining the crude oil and a formulation in an amount of 5 to 3000 ppm based on the amount of crude oil effective for demulsifying the crude oil and forming a mixture, said formulation comprising a mixture of (a) a poly(ethyleneoxide) poly(propyleneoxide) poly(ethyleneoxide) copolymer having the formula ##STR00012## where: w and y numbers are in the range of 10 to 60; R.sub.1 and R.sub.2 radicals are independently represented by the groups H; CH.sub.2(CH.sub.2).sub.AB; CEGJ; CH.sub.2CHLM; CH.sub.2(CH.sub.2).sub.QM; ##STR00013## where: A is a number between 1 and 11, B is H; E, G and J are independently a radical selected from the group consisting of: H, methyl, ethyl, n-propyl, iso-propyl, sec-butyl, iso-butyl, tent-butyl, n-butyl, phenyl, cyclohexyl and cyclopentyl; L is a radical represented by methyl and ethyl, and M is a hydroxyl group; Q is a number between 1 and 5; T is a radical selected from the group consisting of: H, methyl, ethyl, n-propyl, iso-propyl, sec-butyl, iso-butyl, tent-butyl, n-butyl, phenyl, cyclohexyl, cyclopentyl, NO.sub.2, Cl, F and Br; or ##STR00014## where w and y are as defined in Formula 5a; U is a number between 1 and 2; X is oxygen or nitrogen, when X is nitrogen then V is selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, sec-butyl, iso-butyl, tert-butyl, n-butyl, phenyl, cyclohexyl, cyclopentyl, and benzyl; Z is a mono- or di-substitution and is selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, sec-butyl, iso-butyl, tert-butyl, n-butyl, phenyl, cyclohexyl, cyclopentyl, benzyl and hydroxyl; and a synergistic amount of (b) an ionic liquid having a cation selected from the group consisting of 1,5-dicarboxy-pentane-2-ammonium, pyridinium, isoquinolinium, imidazolium, ammonium and ammonium carboxymethane, and an anion selected from the group consisting of R.sub.5COO.sup., Cl.sup., Br.sup., [BF.sub.4].sup.31 , [PF.sub.6].sup., [SbF.sub.6].sup., [R.sub.6SO.sub.4].sup.31 , [OTs].sup., [OMs].sup., where R.sub.5 is an alkyl, cycloalkyl, benzyl, alkenyl, aromatic, or allyl-functionalized chain having 1 and 18 carbon atoms; and R.sub.6 is methyl or ethyl, and mixing the resulting mixture for a time sufficient to demulsify, dehydrate and desalt the crude oil.

19. The method of claim 18, wherein said ionic liquid is selected from the group consisting of triethylammonium methanesulfonate, ethyltrihexylammonium bromide, 1,5-dicarboxy-pentane-2-ammonium methanesulfonate, methyltripentylammonium bromide, ethyltributylammonium ethylsulfate, ethyldodecylimidazolium chloride, and 1,2-dimethylimidazolium methylsulfate.

20. The method of claim 18, wherein said copolymer has a molecular weight between 2200 and 4400 Dalton.

21. The method of claim 20, wherein said formulation is selected from the group consisting of a mixture of 1,5-dicarboxy-pentane-2-ammonium methanesulfonate and said copolymer having a molecular weight of 2200 Dalton; a mixture of methyltripentylammonium bromide and a copolymer having said molecular weight of 4400 Dalton; and a mixture of methyltripentylammonium bromide and said copolymer having a molecular weight of 2200 Dalton.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-A (triethylammonium methanesulfonate) and CF14E (Mn=2200), on crude oil type Akal (19.8 API).

(2) FIG. 2 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-B (ethyltrihexylammonium bromide) and CF14E (Mn=2200), on crude oil type Akal (19.8 API).

(3) FIG. 3 is a graph of water removal rate versus time, showing the activity of the formulations demulsifier IL-C (1,5-dicarboxy-pentane-2-ammonium methanesulfonate) and CF4 and CF19 (Mn=2200), on a crude oil mixture of M+T (17.1) API).

(4) FIG. 4 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-D (methyltripentylammonium bromide) and CF14 (Mn=4400), on crude oil type Bacab (9.2 API).

(5) FIG. 5 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-D (methyltripentylammonium bromide) and CF14 (Mn=2200), on crude oil type Bacab (9.2 API).

(6) FIG. 6 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-D (methyltripentylammonium bromide) and CF17 (Mn=2200), on crude oil type Bacab (9.2 API).

(7) FIG. 7 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-D (methyltripentylammonium bromide) and CF19 (Mn=2200), on crude oil type Bacab (9.2 API).

(8) FIG. 8 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-E (ethyltributylammonium ethylsulfate) and CF19 (Mn=2800), on crude oil type Bacab (9.2 API).

(9) FIG. 9 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-F (ethyldodecylimidazolium chloride) and CF4 (Mn=2200), on crude oil type Bacab (9.2 API).

(10) FIG. 10 is a graph of water removal rate versus time, showing the activity of the demulsifier formulation IL-G (1,2-dimethylimidazolium methylsulfate) and CF4 (Mn=2200), on crude oil type Bacab (9.2 API).

DESCRIPTION DETAILED OF THE INVENTION

(11) Considering the foregoing, and with the purpose of efficiently dehydrating and desalinating medium, heavy and extra heavy crudes oils using in addition lower concentrations of additives; we proceeded to prepare synergistic formulations from our inventions of ionic liquids (IL's) (individually or in formulation) and formulations of triblock copolymers (CF's) of polyoxyethylene-polyoxypropylene-polyoxyethylene with molecular weights in the range of 400 to 4400 Daltons, preferably 800 to 4000 Daltons, and more preferably 1000 to 4000 Daltons, which are bifunctionalized with amines (Cendejas G, et al 2008, Cendejas G, et al 2009, Flores E A, et al 2010). In one embodiment, the copolymer has a molecular weight of 400 to 800 Daltons.

(12) Formulations based on CF's and IL's were evaluated in crudes oil, having gravities are between 8 and 30 API, and preferably 9 and 30 API; their full characterization is described below (Table 2):

(13) TABLE-US-00002 TABLE 2 Physicochemical characteristics of evaluated crudes. RESULTS Heavy Extra- Medium Heavy Mixture heavy PARAMETER METHOD UNIT AKAL TEKEL M + T* BACAB API ASTM-D- API 19.8 14.84 17.1 9.2 287 Salt ASTM- lbs/1000bls 2100** 62** 2600** 8825** D3230 Wax UOP46 % wt 3.0 2.12 4.57 4.24 Water ASTM- % Vol 10.0 2.0 10.0 45 D-4006 Kinematic ASTM- mm.sup.2/s 303 1783.35 777.1 22660.3 Viscosity D-445 Pour point ASTM- C. <42 *** 33 +6 D-97 n-Heptane ASTM- % wt 9.8 20.45 11.85 10.4 insoluble D-3279 Saturates ASTM- % wt 31.6 29.30 34.33 32.0 D-2007-91 Aromatics ASTM-D- % wt 20.6 21.46 20.42 22.8 2007-91 Resins ASTM-D- % wt 35.9 25.15 31.72 28.0 2007-91 Asphaltenes ASTM-D- % wt 11.9 24.09 13.53 17.2 2007-91 *This oil was prepared by mixing 6 volumes of Maya crude oil and 1 volume of Tekel. **Values outside method, dilutions were made to obtain these values. *** Crude oil too heavy, outside method
Evaluation of the Formulations of CF's and IL's as Demulsifier, Dehydrating and Desalting Agents in Median, Heavy and Extra-heavy Crude Oil.

(14) Different concentrated dissolutions were prepared from each one of CF's and IL's, from 5 to 40% by weight, using solvents whose boiling point are in the range of 35 C. to 200 C. Examples of suitable solvents include dichloromethane, methanol, ethanol, isopropanol, chloroform, benzene, toluene, xylene, jet fuel, naphtha, individually or in mixtures of them, so that small volumes of the dissolution were added in order to avoid the influencing effect of the solvent in the rupture of the emulsion. Formulations based on CF's and IL's were evaluated in concentrations between the range from 50 to 3000 ppm

(15) The evaluation procedure is described below: the number of provided graduated bottles with seal and lid, is indicated by the number of compound to evaluate, one more which it corresponds to the crude one without additive; in each one of them the crude was added until 100 milliliters mark. All the bottles were placed in a water bath with temperature controlled at 80 C. for 20 minutes, at the end of this time is added one aliquot of the dissolution of IL's (individual or formulations), FC's and copolymers of commercial formulations mentioned above, all the bottles were shaken for 3 minutes at the rate of 2 blows per second. After being purged, they were placed again in the bath at controlled temperature and the rupture of the emulsion water in oil was followed each 5 minutes during the first 60 minutes, every 10 minutes during the second hour, and finally every hour until the end of the test.

(16) By way of demonstration, that does not imply any limitation, are shown in FIGS. 1-10 the graphic results of the evaluation described above, for different formulations based on CF's and IL's.

Rupture Efficiency in Water/Oil Emulsion Evaluation in Medium Crude Oil

(17) FIG. 1 shows that IL-A dosed at 1500 ppm, removed water with an efficiency of 96%, in other hand the CF-14E additive at 200 ppm removes 81% of water, however it is remarkable the synergism between both compounds, when each one are added formulated at concentrations of 200 ppm, they achieved to remove the water with an efficiency of 91%. This represents a greater efficiency compared to individual CF, and a considerable decrease in concentration of the ionic liquid.

(18) In FIG. 2, it is observed that CF-14E and IL-B, dosed at 200 ppm and 1500 ppm, remove water with efficiencies of 81% and 88% respectively, but when they are formulated each one at concentration of 200 ppm, efficiency achieved is 98%, this represents a significant improvement compared to CF and decrease in the applied concentration of IL.

Evaluation in Heavy Crude Oil

(19) FIG. 3 exemplifies the demulsification efficiencies of two different formulations using the IL-C and two different CF's. Before it is necessary to clarify, that both CF's as IL-C were evaluated individually at concentrations of 200 ppm and 1500 ppm, respectively, and reached efficiencies of around 35%; also was evaluated a commercial formulation owned of IMP (RHS-5) which is composed with breakers, coalescers and clarifiers polymers, in concentrations of 500 and 1000 ppm, achieving zero efficiency. No results corresponding to them were included in the graph in order to facilitate visualization of the same. It is remarkable the synergism between the formulations with CF-19, CF-4 and IL-C, the efficiencies achieved are on the order of 85% and 70% respectively, that representing a significant improvement in water removal, when they are compared with individual efficiencies, and also represents a significant reduction in the concentration of IL-C, reducing from 1500 ppm to 500 ppm of additive. Additionally, the formulations shown in this invention are much better than the commercial formulation RHS-5 when is applied to this type of heavy crude oil.

Evaluation in Extra-Heavy Crude Oil

(20) Considering that in the National Refineries System, there is a growing tendency of processing crudes with decreasing API gravity, it was emphasized the demulsifier research in this kind of crudes, with formulations composed by CF's and IL's, subject of the present invention. The results exemplified below represent an illustration and in no way a limitation.

(21) FIG. 4 shows the ability to break the emulsion of IL-D, CF-14 and the formulation composed by both. When the IL-D was added at 500 ppm water removed is about 20%, and when is added CF-14 (Mn=4400 Daltons) the removal efficiency is 55%, but when the formulation is added, the elimination of water reaches 78% efficiency.

(22) Clearly, is observed the formulation synergism, since the removal of water is greater than the individual application of each component thereof.

(23) FIG. 5 shows the efficiencies in the rupture of the emulsion, when are applied IL-D, CF-14 (Mn=2200 Daltons) and the formulation of both. The IL-D and FC-14, have achieved alone efficiencies of 20% and 45% respectively. When they are combined, a synergism is achieved in the formulation, since their efficiency is 70%.

(24) Also is observed that the formulation broke the emulsion in a shorter time (40 minutes) compared to CF-14 (60 minutes) and the IL-D (80 minutes).

(25) FIG. 6 shows the results of water removal when applying IL-D (500 ppm), CF17 (Mn=2200, 500 ppm) and their formulation (500 ppm/500 ppm). The efficiencies obtained are 20%, 40% and 70% respectively, again the formulation shows synergism. Also the formulation breaks the emulsion before that any of its components individually added.

(26) FIG. 7 shows the behavior of the breaking of the emulsion with respect to time, when IL-D (500 ppm), CF19 (500 ppm) and their formulation (IL-D and CF19 both in a ratio of 500 ppm/500 ppm) were added to the emulsion. The efficiencies obtained were of 20%, 40% and 80%, respectively. Once again the formulation breaks the emulsion before that any of its components individually applied.

(27) FIG. 8 shows that the formulation of the IL-E and CF-19 removes water in 60%, which is superior to the individual efficiencies of the components, since they removes water in a 10% (IL-E, 500 ppm) and 17% (CF-19, Mn=2800 Daltons, 500 ppm), respectively.

(28) FIG. 9 shows the efficiency in the breaking of the emulsion when two formulations of IL-F and CF-4 (Mn=2200 Daltons) are added in different concentrations. Both formulations achieve similar efficiencies from 50 minutes (63%) and hold so until the end of the test, when they reach 68-70% efficiency. It is important emphasize that the individual addition of the components of the formulation (500 ppm), achieve efficiencies close to 35%.

(29) FIG. 10 displays the demulsifier capacity of two formulations formed by IL-G and CF-14 (Mn=4400 Daltons), these formulations were added in different concentrations. Both formulations start to break the emulsion around of the 100 minutes and show similar tendency to achieve efficiencies of around 75% (500 ppm/500 ppm) and 92% (700 ppm/300 ppm), respectively.

Efficiencies in the Salt Removal of the Crude-Oil

(30) TABLE-US-00003 TABLE 3 Evaluation of desalting products and formulations in medium Crude-oil Akal type (API = 19.8, Initial content of salt: 2100 lbs/1000 bls). Final Content % Dehydrating of salt % Product Efficiency Lbs/1000 bls Reduction IL-A/CF14E 91 225 89.3 200 ppm/200 ppm IL -B/CF14E 98 243 88.4 200 ppm/200 ppm IL -A 1500 ppm 96 178 91.5 IL -B 1500 ppm 88 276 86.9 CF14E 200 ppm 81 271 87.0

(31) Table 3 shows the results of dehydrated and desalting test, it is observed that the better yields are achieved with the IL-A at a concentration of 1500 ppm, however with the formulation IL-A/CF14E similar efficiencies are obtained with the addition of lower concentrations, which clearly indicates the synergistic effect produced by the formulation.

(32) TABLE-US-00004 TABLE 4 Evaluation of desalting products and formulations in heavy crude-oil mixture M + T (API = 17.1, Initial content of salt: 2600 lbs/1000 bls) Final content % Dehydrating of Salt % Product Efficiency Lbs/1000 bls Reduction IL -C/CF19 85 262 89.9 500 ppm/500 ppm IL -C/CF4 70 315 87.9 500 ppm/500 ppm IL -C 33 1906 26.7 1500 ppm CF19 35 2180 16.1 200 ppm CF4 38 2090 19.6 200 ppm IMP RHS-5 0.0 2600 0.0 1000 ppm

(33) Respect to heavy crude-oil, the best result in the dehydration and desalting process are obtained with the formulations and are shown in Table 4, their efficiencies are also much better than the commercial formulation (IMP RHS-5).

(34) TABLE-US-00005 TABLE 5 Evaluation of desalting products and formulations in extra-heavy crude oil Bacab type (API = 9.2, Initial content of salt: 8825 lbs/1000 bls). Initial content % Dehydrating of salt % Product Efficiency Lbs/1000 bls Reduction IL-D/CF14 78 900 89.8 (Mn = 4400 Da) 500 ppm/500 ppm IL-D/CF14 70 905 89.7 (Mn = 2200 Da) 500 ppm/500 ppm IL-D/CF17 70 880 90.0 (Mn = 2200 Da) 500 ppm/500 ppm IL-D/CF19 80 826 90.6 (Mn = 2200 Da) 500 ppm/500 ppm IL-E/CF19 60 1100 87.5 (Mn = 2800 Da) 500 ppm/500 ppm IL-F/CF4 70 950 89.2 (Mn = 2200 Da) 700 ppm/300 ppm IL-F/CF4 68 962 89.1 (Mn = 2200 Da) 500 ppm/500 ppm IL-G/CF14 92 513 94.2 (Mn = 4400 Da) 700 ppm/300 ppm IL-G/CF14 75 845 90.4 (Mn = 4400 Da) 500 ppm/500 ppm CF14 55 3120 64.6 (Mn = 4400 Da) 500 ppm CF14 44 3500 60.3 (Mn = 2200 Da) 500 ppm CF17 40 3310 62.5 (Mn = 2200 Da) 500 ppm CF19 40 3255 63.1 (Mn = 2200 Da) 500 ppm CF19 17 5650 36.0 (Mn = 2800 Da) 500 ppm CF4 36 4100 53.5 (Mn = 2200 Da) 500 ppm IL-D 20 6010 31.9 500 ppm IL-E 10 7800 11.6 500 ppm IL-F 35 3960 55.1 500 ppm

(35) Table 5 shows that the greatest efficiency in the dehydrated and therefore in the desalting of crude oil were obtained with the formulations of CF's and IL's

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