Formulations of homopolymers based on alkyl acrylates used as antifoaming agents in heavy and super-heavy crude oils
10213708 ยท 2019-02-26
Assignee
Inventors
- Enrique Cevada Maya (Mexico City, MX)
- Laura Veronica Castro Sotelo (Mexico City, MX)
- Edgar Ivan Hernandez Carbajal (Mexico City, MX)
- Cesar Andres Flores Sandoval (Mexico City, MX)
- Alfonso Lopez Ortega (Mexico City, MX)
- Aristeo Estrada Buendia (Mexico City, MX)
- Fernando Alvarez Ramirez (Mexico City, MX)
- Arquimedes Estrada Martinez (Mexico City, MX)
- Flavio Salvador Vazquez Moreno (Mexico City, MX)
Cpc classification
International classification
Abstract
The present invention relates to the application based on alkyl acrylate homopolymers, such as antifoaming agents in crude oils with densities of 10 to 40 API. Evaluation tests in live crude oil, under similar gas-liquid separation equipment conditions, showed that these polymers based on alkyl acrylate are effective foaming inhibitors in heavy and super-heavy crude oils, reducing the foam between 15 and 50% faster compared to crude oil without an antifoaming agent. Some acrylics show better performance than commercial silicon-based polymers, which suppress foam 20-25% faster than the blank. The antifoaming agents of this invention, based on alkyl acrylate and totally free of silicon, is an advantageous option, to replace the silicone-based foam inhibitors currently on the market.
Claims
1. A process for inhibiting or reducing foam formation comprising the step of feeding crude oil containing natural gas or volatile compounds and having a density of 10 to 40 API to a gas-liquid separation apparatus at a temperature of 50 to 120 , and adding an antifoaming agent formulation in an amount of 100 to 1500 ppm to reduce foam formation by at least 20% by volume relative to the crude oil without the antifoaming agent, said antifoaming agent formulation consisting of an alkyl acrylate homopolymer of formula (1) having a molecular weight of 1,000 to 180,000 Daltons dispersed in an organic solvent and substantially in the absence of water ##STR00002## where: R.sup.1 and R.sup.2 are independent radicals where R.sup.1 is selected from the group consisting of H (hydrogen) and CH.sub.3 (methyl); R.sub.2 is selected from the group consisting of CH.sub.3 (methyl), C.sub.2H.sub.5 (ethyl), C.sub.4H.sub.9 (n-butyl, isobutyl), C.sub.6H.sub.13 (n-hexyl, iso-hexyl), C.sub.8H.sub.17 (2-ethyl-hexyl) C.sub.8H.sub.17 (n-octyl), C.sub.10H.sub.21 (n-decyl, iso-decyl), C.sub.12H.sub.25 (n-dodecyl), C.sub.18H.sub.37 (n-octadecyl), C.sub.8H.sub.9O (2-phenoxyethyl), C.sub.3H.sub.7O (2-methoxyethyl), and C.sub.5H.sub.11O.sub.2 (2-(2-methoxyethoxy)-ethyl); and x is an integer number from 2 to 900.
2. The process of claim 1, wherein X is 20 to 850.
3. The process of claim 1, wherein X is 60 to 600.
4. The process of claim 1, wherein the homopolymers are obtained from monomers consisting of monomers selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, n-amyl acrylate, isobornyl acrylate, isobutyl acrylate, tert-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, 3,5,5-trimethylhexyl acrylate, 2-methoxy ethyl acrylate, 2-phenoxyethyl acrylate, 4-tert-butylcyclohexyl acrylate, octyl acrylate, isodecyl acrylate, decyl acrylate, lauryl acrylate, tridecyl acrylate, octadecyl and behenyl acrylate.
5. The process of claim 1, wherein the homopolymers have a molecular mass 7,000 to 120,000 Daltons.
6. The process of claim 1, wherein the organic solvent has a boiling point of 35 to 200 C.
7. The process of claim 1, wherein the organic solvent is selected from the group consisting of dichloromethane, methanol, ethanol, isopropanol, chloroform, benzene and derivatives, toluene, xylene, jet fuel, naphtha, either individually and in mixtures thereof.
8. The process of claim 1, wherein the concentration of the homopolymer on a dry base is 10 to 50 wt % based on the total weight of the antifoaming agent formulation.
9. The process of claim 1, wherein the homopolymer is included in an amount of 20 to 40 wt % based on the weight of the antifoaming agent formulation.
10. The process of claim 1, wherein the crude oil has a density between 12 to 22 API.
11. The process of claim 1, wherein the antifoaming agent comprises a mixture of two or more of said homopolymers.
12. The process of claim 1, wherein said antifoaming agent formulation is combined with said crude oil in an amount to provide a homopolymer concentration of 200 to 1,000 ppm.
13. A process for inhibiting or reducing foam formation of heavy crude oil in a gas-liquid separation apparatus, said method comprising the step of introducing an antifoaming agent composition into the gas-liquid separation apparatus containing crude oil containing natural gas or volatile compound and having a density of 10 to 4020 API in an amount effective to reduce foam formation by at least in 20% by volume relative to the crude oil without the antifoaming agent, wherein said antifoaming agent composition is added in an amount of 100 to 1500 ppm based on the amount of crude oil, and consists of an alkyl acrylate homopolymer of formula (1) having a molecular weight of 1,000 to 180,000 Daltons dispersed in an organic solvent ##STR00003## where: R.sup.1 and R.sup.2 are independent radicals where R.sup.1 is selected from the group consisting of H (hydrogen) and CH.sub.3(methyl); R.sup.2 is selected from the group consisting of behenyl, 2-pheneoxyethyl, 2-methoxyethyl, 2-(2-methoxyethoxy)-ethyl, isobornyl, and butyl cyclohexyl; and x is an integer number from 2 to 900.
14. The process of claim 13, wherein R.sup.2 is 2-phenoxyethyl.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the first instance,
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DETAILED DESCRIPTION OF THE INVENTION
(10) The method described below was used for the preparation of the homopolymer of alkyl acrylate formulation as an antifoaming agent. This method is illustrative but not limitative.
(11) Homopolymers based on alkyl acrylates are synthesized by semi-continuous emulsion polymerization in latex form, synthetic method described in U.S. Patent Publication No. 2011/0067295, which is hereby incorporated by reference. Latex is a dispersion of polymer particles in water, easy to process because it avoids the use of organic solvents. The final latex is preferably dewatered by distillation at a temperature of 80 to 120 C., and a suitable organic solvent it is added to allow the final application as an antifoaming agent in crude oils with densities between 10 to 40 API, preferably using solvents having a boiling point in the range of 35 to 200 C., such as: dichloromethane, methanol, ethanol, isopropanol, chloroform, benzene and its derivatives, toluene, xylene, jet fuel, naphtha, individually or mixtures thereof. The amount of homopolymer in the solution is in a range preferably from 10 wt % to 50 wt %, and more preferably 20 wt % to 40 wt %.
(12) Formula (1) shows the structure of the different acrylic homopolymers of the present invention, preferably with alkyl esters of acrylic acid or methacrylic acid:
(13) ##STR00001##
(14) where: R.sup.1 and R.sup.2 are independent radicals represented by the groups listed below: R.sup.1H (hydrogen), CH.sub.3 (methyl); R.sup.2CH.sub.3 (methyl), C.sub.2H.sub.5 (ethyl), C.sub.4H.sub.9 (n-butyl, isobutyl), C.sub.6H.sub.13 (n-hexyl, iso-hexyl), C.sub.8H.sub.17 (2-ethyl-hexyl) C.sub.8H.sub.17 (n-octyl), C.sub.10H.sub.21 (n-decyl, iso-decyl), C.sub.12H.sub.25 (n-dodecyl), C.sub.18H.sub.37 (n-octadecyl), C.sub.8H.sub.9O (2-phenoxyethyl), C.sub.3H.sub.7O (2-methoxyethyl), C.sub.5H.sub.11O.sub.2 (2-(2-methoxyethoxy) ethyl). This aliphatic chain can contain heteroatoms from the ether group and benzene type aromatic rings or heteroatomic rings from ether type.
(15) and where:
(16) x=is a number from 2 to 900, preferably 20 to 850, even more preferably from 60 to 600. In addition, the number molecular weights fall within the range of 1,000 to 180,000 Daltons, preferably between 7,000 and 120,000 Daltons.
(17) The following describes, by way of example, implying no limitation, the monomers used in the synthesis of homopolymers objects of the present invention: methyl acrylate, ethyl acrylate, butyl acrylate, n-amyl acrylate, isobornyl acrylate, isobutyl acrylate, tert-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, 3,5,5-trimethylhexyl acrylate, 2-methoxy ethyl acrylate, 2-phenoxyethyl acrylate, 4 tert-butylcyclohexyl acrylate, octyl acrylate, isodecyl acrylate, decyl acrylate, lauryl acrylate, tridecyl acrylate, octadecyl and behenyl acrylate. The water in the resulting homopolymer is removed by distillation at a temperature of 80 to 120 C., and preferably at 90 to 110 C.
(18) The method involves adding an effective amount of homopolymer based on alkyl acrylate to crude oils with densities between 10 to 40 API, preferably from 12 to 22 API, at concentrations between 10 and 2000 ppm, preferably 100 to 1500 and more preferably 200 to 1000 ppm, to inhibit foaming.
(19) The present invention will be described with reference to a number of specific examples which will be considered only as illustrative and not restrictive of the invention. After obtaining the polymer based on alkyl acrylate, were characterized using the following instrumental methods: 1. Size exclusion chromatograph (SEC) Agilent model 1100, with a column type PLgel and using tetrahydrofuran (THF) as eluent, to calculate the molecular weight distributions of the polymers and the polydispersity index (I). 2. Fourier transformed infrared spectrometer, Thermo Nicolet model AVATAR 330, using the method of film technique with the OMNIC software 7.0 version.
(20) The following describes the molecular weights, polydispersity indexes in Tables 1, 2, 3 and 4, and their spectroscopic characteristics from some different alkyl acrylate polymers synthesized, which does not mean any limitation:
(21) Table 1 shows the results for the alkyl polyacrylate (R.sup.1=hydrogen, R.sup.2=n-butyl), which does not mean any limitation:
(22) TABLE-US-00001 TABLE 1 Molecular weight (Mn) and polydispersity indexes (I) of polymers determined by SEC. Polymer Mn (Daltons) I HAB-1 102 250 5.24 HAB-2 45 678 1.81 HAB-3 32 500 2.05 HAB-4 12 050 1.84 HAB-5 8 956 1.69
(23) Table 2 presents the results for the alkyl polyacrylate (R.sup.1=hydrogen, R.sup.2=2-ethyl-hexyl), which does not mean any limitation:
(24) TABLE-US-00002 TABLE 2 Molecular weight in number (Mn) and polydispersity indexes (I) of the polymers determined by SEC. Polymer Mn (Daltons) I HAH-1 85 678 3.72 HAH-2 43 567 2.26 HAH-3 18 768 2.26 HAH-4 9 800 2.38 HAH-5 5 095 3.99
(25) Table 3 shows the results for the polyacrylate alkyl (R.sup.1=hydrogen, R.sup.2=2-methoxyethyl), which does not mean any limitation:
(26) TABLE-US-00003 TABLE 3 Molecular weight in number (Mn) and polydispersity indexes (I) of the polymers determined by SEC. Polymer Mn (Daltons) I HAEM-1 119 780 3.83 HAEM-2 76 890 1.84 HAEM-3 43 300 2.35 HAEM-4 12 987 1.75 HAEM-5 6 973 1.51
(27) Table 4 presents the results for the alkyl polyacrylate (R.sup.1=hydrogen, R.sup.2=phenoxyethyl), which does not mean any limitation:
(28) TABLE-US-00004 TABLE 4 Molecular weight in number (Mn) and polydispersity indexes (I) of the polymers determined by SEC. Polymer Mn (Daltons) I HAEF-1 87 690 2.58 HAEF-2 34 347 2.33 HAEF-3 16 911 3.63 HAEF-4 8 337 2.77 HAEF-5 5 939 4.44
EXAMPLES
(29) The following examples are presented to illustrate the spectroscopic properties of the homopolymers based on alkyl acrylates and its application as antifoaming agents in crude oils with densities in between 10 to 40 API. These examples should not be considered as limiting the claims herein.
HAB-1
(30) Poly (alkyl acrylate) I.R. cm.sup.1: 2983, 2955, 2930, 2870, 1731, 1448, 1394, 1373, 1247, 1155, 1062, 932.
HAB-2
(31) Poly (alkyl acrylate) I.R. cm.sup.1: 2982, 2956, 2930, 2871, 1730, 1446, 1395, 1372, 1247, 1156, 1063, 932.
HAB-3
(32) Poly (alkyl acrylate) I.R. cm.sup.1: 2983, 2954, 2929, 2871, 1730, 1449, 1392, 1370, 1248, 1156, 1061, 934.
HAB-4
(33) Poly (alkyl acrylate) I.R. cm.sup.1: 2981, 2954, 2932, 2874, 1729, 1446, 1392, 1371, 1245, 1154, 1060, 932.
HAB-5
(34) Poly (alkyl acrylate) I.R. cm.sup.1: 2982, 2952, 2932, 2871, 1732, 1447, 1393, 1371, 1249, 1154, 1060, 929.
HAH-1
(35) Poly (alkyl acrylate) I.R. cm.sup.1: 2980, 2953, 2930, 2870, 1733, 1448, 1394, 1373, 1247, 1150, 1066, 932.
HAH-2
(36) Poly (alkyl acrylate) I.R. cm.sup.1: 2988, 2955, 2930, 2871, 1729, 1446, 1395, 1375, 1247, 1165, 1074, 932.
HAH-3
(37) Poly (alkyl acrylate) I.R. cm.sup.1: 2985, 2951, 2929, 2871, 1733, 1449, 1392, 1370, 1248, 1163, 1064, 934.
HAH-4
(38) Poly (alkyl acrylate) I.R. cm.sup.1: 2981, 2954, 2932, 2874, 1729, 1444, 1392, 1370, 1245, 1154, 1060, 932.
HAH-5
(39) Poly (alkyl acrylate) I.R. cm.sup.1: 2983, 2952, 2932, 2871, 1731, 1448, 1390, 1373, 1252, 1159, 1055, 929.
HAEM-1
(40) Poly (alkyl acrylate) I.R. cm.sup.1: 2980, 2948, 2930, 2820, 1729, 1456, 1381, 1252, 1173, 1125, 1026, 862.
HAEM-2
(41) Poly (alkyl acrylate) I.R. cm.sup.1: 2980, 2950, 2930, 2833, 1730, 1448, 1390, 1253, 1170, 1131, 1028, 859.
HAEM-3
(42) Poly (alkyl acrylate) I.R. cm.sup.1: 2982, 2953, 2929, 2826, 1730, 1453, 1384, 1259, 1174, 1127, 1025, 864.
HAEM-4
(43) Poly (alkyl acrylate) I.R. cm.sup.1: 2979, 2951, 2932, 2832, 1729, 1456, 1382, 1260, 1176, 1125, 1026, 862.
HAEM-5
(44) Poly (alkyl acrylate) I.R. cm.sup.1: 2981, 2952, 2930, 2830, 1731, 1452, 1380, 1253, 1178, 1130, 1024, 860.
HAEF-1
(45) Poly (alkyl acrylate) I.R. cm.sup.1: 2948, 2877, 1733, 1451, 1410, 1374, 1173, 1125, 1030, 862.
HAEF-2
(46) Poly (alkyl acrylate) I.R. cm.sup.1: 2954, 2869, 1731, 1457, 1404, 1378, 1171, 1120, 1033, 860.
HAEF-3
(47) Poly (alkyl acrylate) I.R. cm.sup.1: 2948, 2873, 1731, 1452, 1414, 1371, 1173, 1122, 1031, 861.
HAEF-4
(48) Poly (alkyl acrylate) I.R. cm.sup.1: 2953, 2872, 1730, 1452, 1411, 1371, 1174, 1122, 1028, 863.
HAEF-5
(49) Poly (alkyl acrylate) I.R. cm.sup.1: 2948, 2877, 1729, 1452, 1410, 1377, 1173, 1125, 1032, 862.
(50) Polymer Evaluation as Anti-Foaming Agents in Heavy Crude Oil and Super-Heavy
(51) The crude oils employed in the evaluations of the antifoaming agents are contained in a 4 L metal cylinder of stainless steel; oil samples were taken from the well at sampling conditions, of 76.5 C. and a pressure of 6 kg/cm.sup.2.
(52) Homopolymers based on alkyl acrylate were evaluated as inhibitors of foam formation in live heavy and super-heavy crude oils, using an apparatus for measuring the foam and an assessment procedure that Applicants implement (Mexican patent MX/a/2013/013966). The metallic cylinder containing the crude oil were provided with a nitrogen gas supply line, heating jackets and a vent line for the crude oil where the antifoaming agents are fed. The foaming process is induced by preheating the metal cylinder of stainless steel with an outside temperature in a range of 40 to 150 C., preferably between 50 and 120 C., and pressurizing the system with nitrogen gas at a pressure in a range of 80 to 150 psi, preferably between 90 and 130 psi, remaining at these conditions for two hours before starting the test. Once the metal cylinder is at considerable temperature, the crude oil is poured using the output line or vent line, the antifoaming agent is fed into the outlet pipe through a septum-type connection (diaphragm made of a material that allows the entrance of a needle and reseals on removal) by means of a syringe at a desired dosage (10 to 2000 ppm). The foam is formed due to the sudden drop in pressure from the crude oil content in the metallic pressurized container at atmospheric pressure.
(53) 150 mL of crude oil are released from the metal cylinder with foam formed, being poured into a graduated cylinder in approximately 20 to 40 s, preferably between 25 and 35 s. It starts measuring the foam abatement, recording the volumes registered in the graduated cylinder, every minute for a period of 10 min. Finally, once the test is finished, the crude oil in the cylinder remains still until there is no more foam and the residual oil is measured.
(54) Heavy and super-heavy crude oils were characterized as follows:
(55) TABLE-US-00005 TABLE 5 Physical and physicochemical characterization of the crude oils. Property Heavy crude oil Super-heavy crude oil API gravity 15.00 12.84 Salt content (lbs/1000 bls) 49.54 11.48 Paraffin wax content (wt %) 4.32 4.75 Pour point ( C.) 12 3 Kinematic viscosity (mm.sup.2/s) 2309.52 3423.58 @ 25 C. Cryoscopy molecular mass 398.00 426.44 (g/mol) n-heptane insolubles (wt %) 10.45 16.58 SARA analysis Saturates (wt %) 6.06 10.28 Aromatics (wt %) 5.95 26.65 Resins (wt %) 71.71 45.79 Asphaltenes (wt %) 16.22 17.25
(56) Different concentrated dissolutions of each polymer were prepared, from 5 to 40 wt %, using solvents having a boiling point in the range of 35 C. to 200 C., preferably dichloromethane, methanol, ethanol, isopropanol, chloroform, benzene, toluene, xylene, jet fuel, naphtha, either individually or mixtures thereof, so that smaller volumes of solution were added in the test and it was kept out that the effect of the solvent influenced the foam breakdown. Polymers based on alkyl acrylate were evaluated at concentrations ranging from 10 to 2000 ppm. Polymers based on alkyl acrylates were evaluated simultaneously, in a way of comparison, with a commercial silicon-based antifoaming agent (IMP-Si).
(57) By way of proof, which does not imply any limitation, are shown in
(58)
(59)
(60)
(61) In
(62) In
(63) In
(64) In
(65) In
(66) In
(67) Applicants also made mixtures of homopolymers based on alkyl acrylate of the present invention, as an example, does not imply any limitation, we conducted the mixture of HAB-2 and HAH-2 evaluated as antifoaming agent in live heavy and super-heavy crude oils, 15 and 12.84 API, respectively, dosed at 500 ppm in both crude oils, this mixture had a better performance like foam inhibitor compared with the commercial silicon based antifoaming agent (500 ppm) at 10 and 20% more efficient, respectively.