ACS Omega
·
2025
·
IF 4.3
Yongqi Sun,Fujun Sheng,Guangyu Sun,Jiaxuan Wang,Lei Shi
Supercritical CO2 (scCO2) extraction exerts a significant effect on the physicochemical characteristics of crude oil. This work focuses on the role that waxes and asphaltenes played in the scCO2 extraction effect. The extraction rate, hydrocarbon composition, wax precipitation characteristics, conductivity, and centrifugal stability are quantitatively characterized. It is found that the extraction rate of model oil without paraffin wax is the highest after scCO2 treatment, approximately 18.3%. When the paraffin wax content is enlarged from 5.0 to 15.0 wt %, the extraction rate decreases from 16.7% to 11.7%. It is indicated that the presence of wax inhibits the extraction effect of scCO2. In addition, with further addition of asphaltenes, the extraction rate increases and then decreases. This manifests that the addition of asphaltene promotes the extraction effect of scCO2, while the combined effect of waxes and asphaltenes inhibits the extraction effect with the further increase of the asphaltene concentration. Considering the wax precipitation characteristics, the wax appearance temperature (WAT) and wax precipitation amount (WPA) are both increased after scCO2 treatment. With the addition of asphaltene, the WAT and WPA of model oil are both decreased. As for wax crystal morphology, the wax crystals in paraffin wax oil become finer after the treatment, and the amount of wax crystals precipitated increases. Lastly, after scCO2 treatment, the conductivity and absorbance of model oil containing asphaltene decrease, while the light transmittance increases, due to the formation of asphaltene aggregates under scCO2.
研究领域:
石油化学
·
能源科学
✓ 已验证
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Bo Zhang,Chunming Xu,Quan Shi,Yiqiang Li,Zheyu Liu,Jianxun Wu
Supercritical CO2 flooding is an efficient method of enhanced oil recovery in which CO2 injection can selectively extract light components and cause the deposition of residue heavy components in reservoir pores. Residues can change the wettability of the rock surface to ultimately reduce crude oil production. In this study, supercritical CO2 extraction experiments were conducted under identical operation conditions using various minerals, including quartz, montmorillonite, Illite, dolomite, albite, calcite, and chlorite. The crude oil, extracts, and residues were comprehensively characterized using high-temperature gas chromatography and high-resolution mass spectrometry. The results indicate that the extraction effect is influenced by the specific surface areas and adsorption strengths of various minerals. The larger the specific surface area, the more readily the heteroatoms in the resins can be adsorbed onto the rock surface. Quartz exhibits weak adsorption strength toward heteroatoms, whereas minerals with high specific surface areas demonstrate significantly higher adsorption strengths compared to those with lower specific surface areas. The wettability changes of various mineral surfaces were also assessed through contact angle measurements. Upon exposure to crude oil, a rock surface undergoes a transition from being water-wet to becoming oil-wet. Subsequently, it reverts back to being more water-wet due to supercritical CO2 extraction which further proves the feasibility of alleviating channeling by injecting water. Furthermore, the alteration in wettability caused by the change in the carbon number of different heteroatoms under supercritical CO2 extraction is also investigated. This study provides a basis for the mechanism study of CO2–crude oil–rock interaction and a comprehensive understanding of the wettability alteration of different reservoirs in carbon dioxide flooding.
研究领域:
石油工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2016
·
IF 3.611
Tingting Cheng,Yehua Han,Yanfen Zhang,Chunming Xu
A three-step supercritical CO 2 extraction was used for selective fractionation of fast pyrolysis bio-oil. Oxygen-containing compounds in bio-oil and its fractions were characterized using infrared spectroscopy (IR), 1 H nuclear magnetic resonance spectroscopy (NMR), gas chromatography–mass spectrometry (GC–MS) and negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). With appropriate optimization of extraction parameters, lipids, hemicellulose, lignin and condensed aromatics were found enriched in three different fractions. The molecular composition and compound classes were identified by combined analytical techniques, and the selectivity of the fractionation was proved. The compound-type-specific fractionation also facilitated the following characterization and provided insights into the chemical composition of bio-oil. Results indicated that CO 2 supercritical fluid extraction was potential for bio-oil preprocessing.
研究领域:
化学工程
·
分析化学
✓ 已验证
DOI
高影响因子
Foods
·
2024
·Vol. 13
·期 11
·1719
·
IF 4.7
Yadan Chen,Yanbin Wang,Liang He,Liling Wang,Jianchen Zhao,Zhenya Yang,Qin Li,Rui Shi
This study aimed to investigate the efficacy of supercritical CO2(SC-CO2) extraction in enhancing the extraction rate, purity, and antioxidant activity ofIndocalamus latifolius(Keng) McClure (Poaceae) leaf terpenoids (ILLTs). Crude extracts obtained from leaves were subjected to qualitative and quantitative analyses, revealing neophytadiene, phytol, β-sitosterol, β-amyrone, squalene, and friedelin as the primary terpenoid constituents, identified through gas chromatography–mass spectrometry (GC-MS). Compared with steam distillation extraction (SD), simultaneous distillation extraction (SDE), ultra-high pressure-assisted n-hexane extraction (UHPE-Hex), ultra-high pressure-assisted ethanol extraction (UHPE-EtOH), ultrasound-assisted n-hexane extraction (UE-Hex), and ultrasound-assisted ethanol extraction (UE-EtOH), SC-CO2exhibited a superior ILLT extraction rate, purity, and antioxidant activity. Scanning electron microscopy (SEM) observations of the residues further revealed more severe damage to both the residues and their cell walls after SC-CO2extraction. Under optimal parameters (4.5 h, 26 MPa, 39 °C, and 20% ethyl alcohol), the ILLT extraction rate with SC-CO2reached 1.44 ± 0.12 mg/g, which was significantly higher than the rates obtained by the other six methods. The subsequent separation and purification using WelFlash C18-l, BUCHI-C18, and Sephadex LH-20 led to an increase in the purity of the six terpenoid components from 12.91% to 93.34%. Furthermore, the ILLTs demonstrated cytotoxicity against HepG2 cells with an IC50value of 148.93 ± 9.93 μg/mL. Additionally, with increasing concentrations, the ILLTs exhibited an enhanced cellular antioxidant status, as evidenced by reductions in both reactive oxygen species (ROS) and malondialdehyde (MDA) levels.
研究领域:
植物化学
·
药理学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULES
·
2019
·Vol. 24
·期 20
·3732
·
IF 3.06
Li Ji,Zhonghui Qiao,Xin Zhang,Xiaolei Cheng,Weiyang Wang,Fan Zhang,Yifa Zhou,Ye Yuan
Monosialotetrahexosylganglioside (GM1) has good activity on brain diseases and was developed to be a drug applied in clinics for neurological disorders and nerve injury. It is difficult to isolate GM1 in industry scale from the brains directly. In this work, a simple and highly efficient method with high yield was developed for the isolation, conversion, and purification of GM1 from a pig brain. Gangliosides (GLS) were first extracted by supercritical CO2(SCE). The optimum extraction time of GLS by SCE was 4 h, and the ratio of entrainer to acetone powder from the pig brain was 3:1 (v/w). GM1 was then prepared from GLS by immobilized sialidase and purified by reverse-phase silica gel. Sodium alginate embedding was used for the immobilization of sialidase. Under the optimized method, the yield of high-purity GM1 was around 0.056%. This method has the potential to be applied in the production of GM1 in the industry.Keywords:ganglioside;GM1;supercritical CO2extraction;immobilization;sialidase;purification
研究领域:
生物化学
·
药物开发
·
神经科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2019
·
IF 3.021
Shuang Yang,Chuanxian Li,Fei Yang,Xiaoteng Li,Guangyu Sun,Bo Yao
For the pipeline transportation of waxy crude oil, pour point depressants (PPDs) have been developed and used to improve its flowability at low temperature. As supercritical CO2 (scCO2) flooding becomes a common technique to improve oilfield recovery, how the sensitivity of PPD changes due to the degassed crude oil treated by CO2 should be studied. In this work, the effect of scCO2 extraction on the performance of EVA in improving the flowability of Changqing degassed crude oil is investigated by means of a self-developed scCO2 treating equipment, SARA/HTGC analysis, SEM analysis, pour point test, rheological measurement, asphaltene precipitation test, particle size analysis, DSC test, and microscopic observation. The results show that without EVA addition, scCO2 extraction aggravates the flowability of the crude oil at low temperature. The scCO2 extraction extracts light components from asphaltene aggregates causing asphaltenes to precipitate, which inhibits the asphaltenes on playing a role as the natural PPD. As a result, it leads to the formation of smaller needle-like wax crystals with large amount, worsening the flowability of the crude oil. When the EVA is present, however, scCO2 extraction favors the functioning of EVA on improving the flowability of the crude oil at low temperature. The addition of EVA can slightly enhance the solubility of wax molecules thus decreasing the crude oil WAT to some extent, while can significantly change the morphology of precipitated wax crystals from small needle-like to agglomerated clusters, thus improving the flowability of the crude oil. Because of the synergistic effect of EVA and asphaltene aggregates after scCO2 extraction, a more compact EVA–asphaltene–wax ternary crystal structure will form thus further decreasing the pour point, elastic modulus, and equilibrium viscosity at low temperature.
研究领域:
石油工程
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）