TY - JOUR
T1 - Anion and cation effects of ionic liquids and ammonium salts evaluated as dehydrating agents for super-heavy crude oil
T2 - Experimental and theoretical points of view
AU - Flores, César A.
AU - Flores, Eugenio A.
AU - Hernández, Edgar
AU - Castro, Laura V.
AU - García, Antonieta
AU - Alvarez, Fernando
AU - Vázquez, Flavio S.
N1 - Funding Information:
The current study was supported by the Instituto Mexicano del Petróleo , Molecular Engineering Program project number D.01480 . The authors also would like to thank Henry Jankiewicz for the editing work that he did for this paper. The authors would also like to thank M. García Murillo for her assistance.
PY - 2014/8
Y1 - 2014/8
N2 - One series of ionic liquids (IL), [TOA]+ [Y] (where [Y] - = [Cl]-, [HSO4]- or [H 2PO4]-), and new ammonium salts, [OCD] + [Y]- (where [Y] = [HSO4]-, [MeSO3]- or [MePhSO3]-), were evaluated as demulsifying agents for super-heavy crude oil, at API = 6.39° (MO1) and API = 7.13°(MO2), with 8.46 and 8.94 wt.% of asphaltenes, respectively, at dosages of 1000 and 1500 ppm, using a conventional heating bottle test. At 1000 ppm, the ranking of water removal efficiency for the [TOA]+ [Y]- series (in MO1 and MO2, in order to reach 96.7% and 95.4%, respectively) was [Cl]- > [HSO4] - > [H2PO4]-. For the [OCD] + [Y]- series, the rankings for efficiency at 360 min were [HSO4]- > [MeSO3]-, reaching approximately 27% in MO2, whereas [MePhSO3]- reached 1% in MO2. At a dosage of 1500 ppm, the [TOA]+ [Y]- series achieved 100% water removal, showing the same order at 1000 ppm. For [OCD] + [Y]-, the order at 24 h was [HSO4] - > [MeSO3]- > [MePhSO3] - for MO1 and MO2 at maximums of 85.5% and 92.3%, respectively. [OCD]+ [HSO4]- was an efficient demulsifier in tests of long duration. Quantum parameters were obtained at the semiempirical RM1 level, in order to establish a correlation with the experimental results. The molecular volume (VM), molecular refractivity (MR), dipolar moment (μ) and mean polarizability (α) of the cation and anion fragments were important factors driving the dewatering process. VM, MR and α were shown to have a direct relationship with water removal efficiency. Furthermore, absolute softness and the electrophilicity index of the cation fragments were calculated at the density functional theory (DFT) level. An increase in the softness and electrophilicity of the cations correlated with lesser effectiveness as demulsifiers. Finally, the partition coefficient of the cations showed that if the viscosity of the crude oil is low, it is possible to use ILs with a low partition coefficient (log P), but if the viscosity is high, the log P of IL should be near the [TOA]+ [Cl]- value.
AB - One series of ionic liquids (IL), [TOA]+ [Y] (where [Y] - = [Cl]-, [HSO4]- or [H 2PO4]-), and new ammonium salts, [OCD] + [Y]- (where [Y] = [HSO4]-, [MeSO3]- or [MePhSO3]-), were evaluated as demulsifying agents for super-heavy crude oil, at API = 6.39° (MO1) and API = 7.13°(MO2), with 8.46 and 8.94 wt.% of asphaltenes, respectively, at dosages of 1000 and 1500 ppm, using a conventional heating bottle test. At 1000 ppm, the ranking of water removal efficiency for the [TOA]+ [Y]- series (in MO1 and MO2, in order to reach 96.7% and 95.4%, respectively) was [Cl]- > [HSO4] - > [H2PO4]-. For the [OCD] + [Y]- series, the rankings for efficiency at 360 min were [HSO4]- > [MeSO3]-, reaching approximately 27% in MO2, whereas [MePhSO3]- reached 1% in MO2. At a dosage of 1500 ppm, the [TOA]+ [Y]- series achieved 100% water removal, showing the same order at 1000 ppm. For [OCD] + [Y]-, the order at 24 h was [HSO4] - > [MeSO3]- > [MePhSO3] - for MO1 and MO2 at maximums of 85.5% and 92.3%, respectively. [OCD]+ [HSO4]- was an efficient demulsifier in tests of long duration. Quantum parameters were obtained at the semiempirical RM1 level, in order to establish a correlation with the experimental results. The molecular volume (VM), molecular refractivity (MR), dipolar moment (μ) and mean polarizability (α) of the cation and anion fragments were important factors driving the dewatering process. VM, MR and α were shown to have a direct relationship with water removal efficiency. Furthermore, absolute softness and the electrophilicity index of the cation fragments were calculated at the density functional theory (DFT) level. An increase in the softness and electrophilicity of the cations correlated with lesser effectiveness as demulsifiers. Finally, the partition coefficient of the cations showed that if the viscosity of the crude oil is low, it is possible to use ILs with a low partition coefficient (log P), but if the viscosity is high, the log P of IL should be near the [TOA]+ [Cl]- value.
KW - Ammonium salts
KW - Crude oil
KW - DFT level
KW - ILs
KW - RM1 level
KW - Water removal
UR - http://www.scopus.com/inward/record.url?scp=84899033287&partnerID=8YFLogxK
U2 - 10.1016/j.molliq.2014.03.044
DO - 10.1016/j.molliq.2014.03.044
M3 - Artículo
SN - 0167-7322
VL - 196
SP - 249
EP - 257
JO - Journal of Molecular Liquids
JF - Journal of Molecular Liquids
ER -