INTERFACIAL ENERGY DURING THE EMULSIFICATION OF WATER-IN-HEAVY CRUDE OIL EMULSIONS

Karcher, V.; Perrechil, F. A.; Bannwart, A. C.

doi:10.1590/0104-6632.20150321s00002696

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Brazilian Journal of Chemical Engineering

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Sumário

KINETICS AND CATALYSIS; REACTION ENGINEERING; AND MATERIALS SCIENCE • Braz. J. Chem. Eng. 32 (1) • Jan-Mar 2015 • https://doi.org/10.1590/0104-6632.20150321s00002696 copy

INTERFACIAL ENERGY DURING THE EMULSIFICATION OF WATER-IN-HEAVY CRUDE OIL EMULSIONS

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

The aim of this study was to investigate the interfacial energy involved in the production of water-in-oil (W/O) emulsions composed of water and a Brazilian heavy crude oil. For such purpose an experimental set-up was developed to measure the different energy terms involved in the emulsification process. W/O emulsions containing different water volume fractions (0.1, 0.25 and 0.4) were prepared in a batch calorimeter by using a high-shear rotating homogenizer at two distinct rotation speeds (14000 and 22000 rpm). The results showed that the energy dissipated as heat represented around 80% of the energy transferred to the emulsion, while around 20% contributed to the internal energy. Only a very small fraction of the energy (0.02 - 0.06%) was stored in the water-oil interface. The results demonstrated that the high energy dissipation contributes to the kinetic stability of the W/O emulsions.

Emulsion; Interfacial energy; Energy balance; Droplet size

Property	Value	Measurement method
Viscosity (25 °C)	2250 mPa.s	Haake Rheostress rheometer (Haake, Germany)
Specific gravity (25 °C)	0.96	Densimeter
Moisture content	0.24%	Karl Fisher 701 KF Titrino (Metrohm, Switzerland)
Surface tension (25 °C)	0.0315 N.m^-1	Sigma 701 tensiometer (KSV Instruments, Finland)
Water-oil interfacial tension (25 °C)	0.0275 N.m^-1
Specific heat (20-100 °C)	1.65 J.g^-1.K^-1	Differential scanning calorimetry
Asphaltene content (C5I)	9%	C5I and C7I were obtained by precipitation with n-pentane and
Asphaltene content (C7I)	3%	n-heptane, respectively (methodology described by *Santos et al. (2006)*Santos, R. G., Mohamed, R. S., Bannwart, A. C. and Loh, W., Contact angle measurements and wetting behavior of inner surfaces of pipelines exposed to heavy crude oil and water. Journal of Petroleum Science and Engineering, 51, 9-16 (2006).)
Naphthenic acid content	0.5%	Methodology described by *Santos et al. (2006)*Santos, R. G., Mohamed, R. S., Bannwart, A. C. and Loh, W., Contact angle measurements and wetting behavior of inner surfaces of pipelines exposed to heavy crude oil and water. Journal of Petroleum Science and Engineering, 51, 9-16 (2006).

Fluid	Rotation speed	14000 rpm				22000 rpm
Fluid	T_inlet (°C)	15	25	35	45	15	25	35	45
Glycerine	Ẇ_input(W)	85.6	79.2	62.5	64.1	226.4	218.4	206.4	186.5
	(W)	45.3	39.9	30.5	25.9	106.4	97	86.7	79.7
	Ẇ_losses (W)	40.2	39.3	32.0	38.2	120	121.5	119.7	106.8
	^δẆ_losses (W)	6.7	7	7.6	7.6	4.6	4.6	5.1	4.8
	η (%)	53	50	49	40	47	44	42	43
Crude oil	Ẇ_input(W)	79.7	71.9	65.1	63.4	182.2	180.9	195.4	188.7
	(W)	46	41.3	31.2	29	94.8	95.1	94.5	81.7
	Ẇ_input(W)	33.7	30.5	33.9	34.5	87.4	85.7	100.9	107
	^δẆ_losses (W)	6.8	7.1	7.6	8	4.7	4.8	4.7	4.8
	η (%)	58	57	48	46	52	53	48	43

Agitation speed (rpm)	Water volume fraction	n (-)	η_100s^-1 (mPa.s)	R²
	0.1	1.00	2778	0.998
14000	0.25	1.00	5685	0.999
	0.4	0.92	9922	0.996
	0.1	1.00	3549	0.998
22000	0.25	1.00	5655	1.000
	0.4	0.82	10560	0.979

Agitation speed ^(rpm)	Water volume fraction	Ẇ_input (W)	(W)	Ẇ_losses (W)	η (%)
14000	0.1 0.25 0.4	86.0 ± 5 97.3 ± 6 95.5 ± 6	48.3 ± 2 51.0 ± 2 51.8 ± 2	37.7 ± 3 46.4 ± 3 43.7 ± 3	56 52 54
22000	0.1 0.25 0.4	196.0 ± 9 203.0 ± 9 196.7 ± 9	93.0 ± 2 102.7 ± 2 97.6 ± 2	103.0 ± 5 100.3 ± 5 99.1 ± 5	47 51 50

Agitation speed (rpm)	Water volume fraction	A_i/V (m^-1)	u_iA_i/V (J/cm³)	u_iA_i/W_u(%)
14000	0.1 0.25 0.4	13 000 31 000 42 000	0.09 ± 0.03 0.22 ± 0.05 0.26 ± 0.05	0.019 ± 0.007 0.051 ± 0.012 0.061 ± 0.012
22000	0.1 0.25 0.4	30 000 42 000 58 000	0.22 ± 0.09 0.20 ± 0.05 0.21 ± 0.03	0.028 ± 0.011 0.025 ± 0.006 0.025 ± 0.004

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