Lingwei Meng

Influence of Water Content and Temperature on Stability of W/O Crude Oil Emulsion

Water content of W/O crude oil emulsion and temperature have great influence on stability of the W/O crude oil emulsion and the subsequent demulsification process especially for oil-water treatment centers using a two-step sedimentation demulsification process in Jilin oilfield. Electrical microscope and Turbiscan stability analyzer were employed to investigate the influence of water content and temperature on stability of synthetic W/O emulsion. The results show that the average water droplets size decreases when water content decreases, the emulsion stability decreases when water content or holding temperature increases, and the emulsion stability constant and the temperature have a linear relationship.

Synthesis, Aggregation Behavior and Emulsification Characteristic of a Multi-sticker Amphiphilic Polymer

A multi-sticker amphiphilic polymer P(AM-NaA-DCHAM) was synthesized using micellar polymerization. Fluorescent spectroscopy, rheology and SEM were used to characterize the aggregation behavior of P(AM-NaA-DCHAM) solutions. Above CAC, aggregation formed by intermolecular association of hydrophobic groups can induce large quantities of hydrophobic microdomains and strong elastic polymer gel network structures in P(AM-NaA-DCHAM) solutions. O/W crude oil emulsions stabilized by P(AM-NaA-DCHAM) were prepared, and a laser particle size analyzer and Turbiscan lab stability analyzer were employed to study their stability. O/W crude oil emulsions stabilized by P(AM-NaA-DCHAM) get more stable as polymer concentration increases. The stability mechanism of O/W crude oil emulsions stabilized by P(AM-NaA-DCHAM) is probably because the elastic polymer gel structure of P(AM-NaA-DCHAM) in the continuous phase has the ability to hold oil droplets.

Research on association between multi-sticker amphiphilic polymer and water-soluble β-cyclodextrin polymer

The host cyclodextrin polymer-P(AM/A-β-CD/NaA) is prepared by redox free-radical copolymerization. Additionally, the multi-sticker amphiphilic polymer-P(AM/BHAM/NaA) as a guest polymer is synthesized using micellar polymerization. The copolymer structures are characterized by 1H NMR. Subsequently, all the polymers and inclusion complexes are evaluated in terms of apparent viscosity, optical absorption spectra and rheological property. The results indicate that the inclusion association between the cyclodextrin group (CD) and multi-sticker hydrophobic monomer (BHAM) is in accordance with ternary interaction (CD/BHAM = 2:1). Because of the inclusion association between the host and guest polymers, the solution of inclusion complex has much higher viscoelasticity even under the low amphiphilic polymer concentration. When the molar ratio of CD to BHAM is 1:1, the critical aggregation concentration (CAC) of the inclusion complex solution still remains. Furthermore, above the CAC, two types of associations, inclusion association and inter-molecular hydrophobic association, can occur in the complex solution and these interactions were also verified by fluorescence spectroscopy and atomic force microscopy (AFM). In this paper, the inclusion rule of cyclodextrin polymer with the multi-sticker amphiphilic polymer is discussed, and the rule of the enhanced solution viscosity is further explored.

Study on shearing resistance and the stability of O/W emulsion of the inclusive and hydrophobic association systems by activation energy methodology

The different polymer networks were constructed by two kinds of associations, one is host-guest inclusion between P(AM/A-β-CD/NaA) and P(AM/BHAM/NaA), and the other is hydrophobic association of P(AM/BHAM/NaA). Under the high-speed shearing, the viscosity survival and recovery rate of different systems were investigated. The results show the inclusion complex (CD:BHAM = 2:1) has excellent shearing resistance performance, and it was also verified by dynamic light scattering (DLS). This is mainly because the strength of inclusive association is stronger than that of hydrophobic one. The conclusion was proved by time-temperature superposition as well. It shows that the activation energy Ea of the inclusion complex (CD:BHAM = 2:1), which represents the strength of association, has a maximum value, while the activation energy Eb of P(AM/BHAM/NaA) has also a maximum one because of the multiple associative sites of hydrophobic associations. The activation energy values of the inclusion complex (CD:BHAM = 1:1) are intermediate since there are two kinds of associations in this solution. This is exactly the reason that the complex (CD:BHAM = 1:1) has the best emulsifying property. Moreover, the conclusions related to emulsifying property have been verified by using a laser particle size analyzer and Turbiscan lab stability.

Study on Interfacial Tension Between Alkanolamide Surfactants of Different Carbon Structure and Daqing Crude Oil

A study was done on the interfacial tension between Daqing crude oil and solutions of alkanolamide surfactants with different carbon chain structures which were made of reproducable plants or animals. These surfactants included plant oil acid diethalkanolamide (POAD), lauric acid diethalkanolamide (LAD), myristic acid diethalkanolamide (MAD), palmic acid diethalkanolamide (PAD) and stearic acid diethalkanolamide (SAD) and their combined systems. The results indicated that the longer the carbon chain, the better the interfacial activity. There is an optimum carbon chain length when the surfactant concentration is low. According to the molecular structure of the alkanolamide surfactant, the mechanism of ultra-low interfacial tension of different systems was discussed. The surfactant with mixed carbon chains promotes tight arrangement of the surfactant molecule at interface. So the interfacial tension characteristics were explained microscopically between different surfactant systems and Daqing crude oil. The effects of sodium chloride on the interfacial tension (between POAD + MAD surfactant with Daqing crude oil) were discussed. The higher the surfactant concentration of the POAD + MAD system, the higher the sodium chloride concentration was needed to reach ultra-low interfacial tension.

High-temperature performance and microstructure of composite modified hard asphalt

ABSTRACT Composite modified hard asphalt (CMHA) was prepared by four-step high-speed shearing method adding crumb rubber, styrene-butadiene-styrene (SBS) copolymer, and hard asphalt to QHD AH-70 neat asphalt. The high-temperature performance and microstructure of CMHA were evaluated by rotational viscometer, fluorescence microscopy, and infrared spectroscopy, through which the modification mechanism was proposed. The results show that the shearing time had great influence on the high-temperature performance of CMHA. A significant variation in phase morphology of CMHA during preparation was observed. It is found that phase morphology was converted from a continuous asphalt phase with dispersed polymer phase to two twisted continuous phases, then to a continuous asphalt phase with dispersed polymer phase again. Preparation of CMHA was a complex physical and chemical process. A fraction of SBS took part in the chemical reaction and others were dispersed in net structure, which is beneficial for workability and performance of asphalt.