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The viscosity of the heavy oil was closely correlated with its own resin content by comparing three types of crude oil. In this paper, two novel viscosity reducers with characteristic groups in molecular structures were synthesized for Xinjiang heavy oil, namely viscosity reducer 1 (VR-1) and viscosity reducer 2 (VR-2), both of them showed the better viscosity reduction effect on Xinjiang heavy oil and VR-2 was better than VR-1. The measurement results of ultraviolet-visible spectrophotometer and scanning electron microscope showed that the VR-2 had better separation effect for resin than the VR-1. By analyzing the infrared spectrum results of resin molecule, it could be seen that the resin molecule contained more heteroatoms, which could more easily form the stronger hydrogen bonding with VR-2 with more polar groups to result the better resin dispersion effect. Hence, the phenomenon that VR-1 was not as good as VR-2 in improving fluidity of Xinjiang heavy oil was explained. Key words: resin, viscosity reducer, heavy oil, 1. Introduction Heavy oil refer to viscous crude oil with poor fluidity, which caused great difficulties in all aspects of heavy oil production. (1-3) In some way, the flow performance [...]

A nanoparticle viscosity reducer has been shown to reduce the viscosity of heavy oil effectively. Carbon nanoparticles (CNPs) are environmentally friendly materials with good application prospects and biocompatibility. In this research, hydroxyl CNPs with phenyl groups on their surface were synthesized and used to reduce viscosity and improve fluidity in heavy oil. The effects of the CNPs on the rheological properties of heavy oil and their ability to reduce viscosity were measured using a rheometer and a rotational viscometer. The CNP viscosity reducer decreased the viscosity of Tahe heavy oil by up to 65.89%, with the introduction of long-chain alkyl groups affecting the viscosity reduction performance. The asphaltene structure was studied using X-ray diffraction and Raman spectroscopy, which showed that the microcrystalline structural parameters of asphaltene changed after the interaction with the CNP viscosity reducer. The effect of the viscosity reducer on the intermolecular hydrogen bonds of asphaltene was studied using Fourier-transform infrared and proton nuclear magnetic resonance spectroscopies, which showed that the interaction with the viscosity reducer destroyed the original hydrogen bonds within the asphaltene. The CNP viscosity reducer decreases the accumulation height of asphaltene aggregates by changing the microcrystalline structural parameters of asphaltenes and dispersing asphaltene aggregation structures, thereby reducing the viscosity of heavy oil. [ABSTRACT FROM AUTHOR]

The addition of salt can irreversibly disrupt the stability of both emulsions and polymer latex. The reversible conversion of amines into organic ammonium salts can be induced by CO2 stimulation, thereby enabling the switching of colloids. The switchable amine, tris[2‐(dimethylamino)ethyl]amine (Me6TRAN), was selected for the study. The electrical conductivity of an aqueous solution of Me6TRAN is modulated by the introduction and removal of CO2. The critical micelle concentration of sodium dodecyl benzene sulfonate (SDBS) was observed to decrease from 1.0 × 10−3 to 5.0 × 10−4 M upon the introduction of Me6TRAN, as confirmed by surface tension measurements conducted under CO2. The emulsion of crude oil, which comprised of SDBS and Me6TRAN, underwent reversible destruction and restoration upon exposure to CO2 and N2. The PMMA latex exhibited a clear phase separation subsequent to CO2 sparging, but attained homogeneity upon N2 sparging. This study is anticipated to introduce a novel avenue for emulsion or polymer latex that can undergo demulsification and emulsification through CO2 stimulation. [ABSTRACT FROM AUTHOR]

In order to reduce the impact of greenhouse gases on the environment, the development of various new CO2 capture materials has become a hot spot. In this work, a novel composite amine solid adsorbent was prepared by simultaneously using tetraethylenepentamine (TEPA) and 2-[2-(dimethylamino) ethoxy] ethanol (DMAEE) for amine functionalization on the polyester microsphere carrier. The introduction of methyl methacrylate (MMA) with high glass transition temperature into the polyester carrier makes the carrier microspheres have high hardness. At the same time, the carrier also contains active epoxy groups and hydrophobic glycidyl methacrylate (GMA, which can undergo ring-opening reaction with composite amines to achieve high-load and low-energy chemical grafting of amines on the carrier. The composite aminated polyester microspheres were used as an efficient adsorbent for CO2 in simulated flue gas. The results show that the synergistic effect of TEPA-DMAEE composite amine system in the adsorbent is beneficial to the improvement of CO2 capture capacity. When the total amine content in the impregnating solution is 45 wt% and the composite amine ratio is TEPA: DMAEE = 6: 4, the CO2 adsorption capacity can reach the optimal value of 2.45 mmol/ g at 70 °C. In addition, the composite amine microsphere adsorbent has cyclic regeneration performance. Importantly, through kinetic fitting, the Avrami kinetic model fits the CO2 adsorption better than the quasi-first-order and quasi-second-order kinetic models, which proves that physical adsorption and chemical adsorption coexist in the adsorption process. This simple, long-term stable and excellent selective separation performance makes amine-functionalized adsorbents have potential application prospects in CO2 capture. [ABSTRACT FROM AUTHOR]

The introduction of external CO2 could reversibly convert tertiary amines into quaternary ammonium salts, enabling demulsification/emulsification switching of emulsions or latexes. However, CO2‐switchable oligomeric or low‐molecular‐weight polymeric surfactants are rarely researched. In this study, 2‐(dimethylamino)ethyl methacrylate and stearyl methacrylate are chosen to synthesize a switchable oligomeric surfactant (OS). The conductivity of OS aqueous solution (0.2 wt%) increased from 14.0 to 329 μS cm−1 by adding and removing CO2, which proved a good performance of OS in response to the CO2 stimulus. The most important finding was that the crude oil emulsion containing OS was reversibly degraded and re‐formed by the alternate CO2 and N2 treatment. In contrast to that, the investigated PS latex system underwent apparent stratification after the N2 bubbling, but it regained a homogeneous phase upon the N2 bubbling. The particle size of PS latex varied between 245 nm and 130 μm, and zeta potential changed from −43.2 to −5.8 mV, which demonstrated that the PS latex stability might break and recover by addition and removal of CO2. This work is expected to open a new window for the CO2‐stimulated reversible emulsification of emulsions or polymer latexes. [ABSTRACT FROM AUTHOR]

Hydrophobic long carbon chains (C16) were grafted onto the main chains of Xanthan Gum by etherification under the ordered conformation of Xanthan. Rheology and pyrene fluorescence spectroscopy experiments discovered that the critical association concentration (CAC) of modified Xanthan solution was 0.16%, and ANS fluorescence probe test indicated modified Xanthan had better hydrophobic association effect than before. Additionally, macroscopic and microscopic properties of modified Xanthan solutions, as well as the effects of temperature and salt on its association behavior were explored by rheology and scanning electron microscopy (SEM), revealed the reason of the improvement of modified Xanthan properties in micro levels. The results show that the modified Xanthan had better high-temperature resistance, which retained 421 mPa·s at 140 °C, about four times the apparent viscosity of Xanthan before modification (125 mPa·s). Adding NaCl up to the salt concentration of 4.0%, modified Xanthan still maintained well spatial network structure and a high apparent viscosity (728 mPa·s), while the apparent viscosity of Xanthan before modification was much lower than 728 mPa·s. Since the hydrophobically modification didn't change the structure of Xanthan, the improvement of the above properties all came from the contribution of hydrophobic chain graft. [ABSTRACT FROM AUTHOR]