He Liu

University of Petroleum (East China), Tsingtao, Shandong Sheng, China

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Publications (14)34.08 Total impact

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    ABSTRACT: Information on distribution of metals and metalloporphyrins can help to understand molecular interaction presented by metals and asphaltenes and possible participation of metals in aggregation of asphaltenes. Therefore, contents of metals and metalloporphyrins were determined in three asphaltene subfractions separated based on solubility. Compositions of the subfractions were confirmed by elemental analysis, vapor pressure osometry molecular weight, and 1H NMR, and molecular structures were simulated. The correlation between distribution of metals and metalloporphyrins and molecular composition was discussed. It indicates that metals interacting loosely with asphaltenes tend to be preferentially extracted into lighter fractions and present as metalloporphyrins, while a great portion of metals concentrates into the heavier fraction and presents as metal-nonporphyrins apparently due to strong interaction with asphaltenes. This suggests that distribution of metals plays a key role in determining the polarity and solubility of subfractions, and thus affects aggregation of asphaltenes.
    No preview · Article · Aug 2015 · Journal of Dispersion Science and Technology
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    ABSTRACT: Petroporphyrins were enriched and purified from atmospheric residues of two typical heavy oils, Canadian oil sand bitumen (OSAR: Ni, 80 ppm; V, 190 ppm; S, 3.97 wt %) and Chinese Liaohe heavy oil (LHAR: Ni, 68.7 ppm; V, 1.81 ppm; S, 0.36 wt %) by silica-gel chromatography. The separation and purification were confirmed by atomic absorption spectroscopy (AAS) combined with UV-vis spectroscopy, and the petroporphyrins were characterized by positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Vanadyl and nickel porphyrins in OSAR are simultaneously identified by mass measurement and isotopic fine structure. Vanadyl porphyrins with structures of N4VO, N4VO2, and N4VOS are all detected as protonated analyte ([M + H]+). Both molecular ion (M+•) and protonated analyte ([M + H]+) as well as their corresponding isotopes are observed for N4Ni porphyrins in OSAR and LHAR with an average mass resolving power of over 400000 (m/Δm50%). This is rarely detected by FT-ICR MS using ESI technique previously. Formation of molecular ion can be attributed to the low oxidation potential of nickel porphyrins, the effect of oil matrix on the solution conductivity, and the relatively low flow rate of solution into the capillary. Three more highly unsaturated types of N4VO porphyrins were identified in addition to the six well-documented structures. Compared to N4VO porphyrins, N4VOS porphyrins present higher DBE ranging from 21 to 27 while N4VO2 porphyrins show lower DBE ranging from 18 to 20 and narrower carbon number distribution, suggesting possible different origins of sulfur (pyrolysis of kerogen) and oxygen (diagenesis of chlorophyills). Ni/V and the ratio of relative abundance of ETIO porphyrins to DPEP porphyrins (-ETIO/-DPEP) for nickel porphyrins indicate that Liaohe oil and Canadian oil sand bitumen are continental and marine sediments, respectively, and Liaohe oil has a higher maturity. Enrichment by the simple chromatographic method facilitates the mass spectral identification of nickel porphyrins even for heavy residue with low content of nickel and high content of sulfur.
    Full-text · Article · Jul 2015 · Energy & Fuels
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    ABSTRACT: Anthracene (ANT) was applied as the accepting probe to evaluate the hydrogen transfer ability of a Venezuela petroleum residue and its subfractions (i.e., saturates, aromatics, resins, and asphaltenes) under different atmospheres and reaction conditions. The hydrogen donating ability (HDA) of H2, HDA of the fractions, and synergism between fractions and H2 were analyzed. The results show that the temperature, initial hydrogen pressure, and time have a positive effect on the HDA of hydrogen. The HDA of all of the subfractions increases clearly with increasing temperature, both under nitrogen and hydrogen, before an equilibrium is achieved, and the HDA determined under hydrogen is higher than that measured under nitrogen. The saturates (Sa) and aromatics (Ar) showed a positive synergism with hydrogen, whereas the resins (Re) and asphaltenes (Asp) showed a negative one according to the calculated synergism. The summation HDA determined under nitrogen was significantly lower than the original HDA of the Venezuela petroleum residue, whereas the trend for hydrogen was the opposite.
    No preview · Article · Mar 2015 · Energy Technology
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    ABSTRACT: The potential catalytic performance of metalloporphyrins (MPs) for the hydrogenation of anthracene was investigated. The hydrogenation of anthracene with MPs, sulfur, or a combination of both was investigated. The MPs showed a small amount of catalytic activity for the hydrogenation reaction. Sulfur markedly improved the catalytic activity of the MPs. To probe demetalation of the MPs and the formation of catalytic species, conversions of the MPs were evaluated by UV/Vis spectroscopy. The solids formed in situ with α-Al2O3 as a carrier during the hydrogenation with nickel tetraphenylporphyrin and sulfur were characterized by Raman, X-ray photoelectron (XPS), and energy-dispersive X-ray spectroscopy (EDS). In the presence of sulfur, high conversions of the MPs were obtained. Raman spectroscopy, XPS, and EDS analyses suggested that the catalytic species were mixtures of different nickel sulfide phases with NiS as the main component. Thus, with the aid of sulfur, the MPs could be readily demetalated and then sulfided to catalytic species, and thus it is possible to activate inherent MPs to improve the hydroconversion of heavy oil.
    No preview · Article · Dec 2014 · Energy Technology
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    ABSTRACT: A series of thermal cokes obtained by coking of vacuum residues and fractions have been studied by polarized light microscopy observation, scanning electron microscope (SEM), and temperature-programmed oxidation (TPO) technique. The anisotropic degrees of coke samples are found to be considerably different for discriminating characterization, which indicates that the coke morphology is closely dependent on the chemical nature of the coking materials. The restricted mesophase development in thermal coke might be ascribed to the increasing amount of heteroatoms contained in the parent coking materials. A proper signal analysis procedure of TPO profiles was obtained to discriminate the carbon species in the coke quantitatively, and then a good one-to-one correlation between determinations by polarized-light micrographs analysis and TPO method was observed, which shows that the TPO technique could be a suitable and more rapid method than polarized-light microscopy to quantitatively assess the morphology of coke, even in some situations in which the traditional method is inadequate.
    No preview · Article · Nov 2013 · Fuel
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    ABSTRACT: Co-carbonization of asphaltenes and one of maltene fractions has been carried out in a bench scale unit in order to quantitatively study the effect of interaction on the morphology and oxidation performance of resultant coke. Two asphaltic vacuum residues are prepared from a Venezuelan crude oil and a Chinese Liaohe crude oil as the parent feedstocks. A positive synergic effect upon coke yield and morphology, which increases as the maltene fraction becomes more aromatic and hydrogen-donable, is observed for both blending systems. Oxidation reaction characteristics of cokes have been analyzed in order to determine the thermal performance under oxygen atmosphere. It is concluded that proper selection of blending petroleum feedstocks during coking process would promote the coke quality and oxidation performance (i.e. higher enthalpy of burning) in addition to reducing the yield of coke, which could partly offset the reduced economic value brought out by the relatively low liquid yield when rather inferior petroleum feedstocks are processed. (c) 2013 Elsevier B.V. All rights reserved.
    No preview · Article · Jul 2013 · Journal of Analytical and Applied Pyrolysis
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    ABSTRACT: Background This study aimed to investigate the level of awareness of and factors associated with major infectious diseases in rural China and to provide the most recent baseline data for the prevention and control of these diseases. Methods This cross-sectional study was carried out in Zhejiang province between December 2010 and April 2011. Participants were recruited from 36 villages and interviewed by doctors from the community health service using a structured questionnaire. Results The study sample consisted of 36,377 subjects aged 15 to 80 years old. Study results showed that knowledge of HIV was adequate in 44.21% of rural residents; knowledge of TB was adequate in 52.66% of respondents; and knowledge of HBV was adequate in 60.18% of respondents. People in older age groups and with lower education levels were more likely to have low levels of awareness of these three infectious diseases. Participants in the farming industry had poorer awareness of HIV and HBV, while students and factory workers knew little of TB. The proportions of people reporting being fully satisfied with the control policies for HIV, TB and HBV were 37.70%, 34.25% and 36.12%, respectively. Conclusions The level of awareness of HIV, TB and HBV is still low among rural residents. Further national disease control plans for major infectious diseases should emphasise effective and comprehensive health education campaigns to increase public awareness of these diseases in rural areas of China.
    Full-text · Article · Apr 2013 · BMC Infectious Diseases
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    ABSTRACT: To examine the association of living arrangements with functional disability among older persons and explore the mediation of impact factors on the relationship. Cross-sectional analysis using data from Healthy Aging study in Zhejiang Province. Analyzed sample was drawn from a representative rural population of older persons in Wuyi County, Zhejiang Province, including 1542 participants aged 60 and over in the second wave of the study. Living arrangements, background, functional disability, self-rated health, number of diseases, along with contemporaneous circumstances including income, social support (physical assistance and emotional support). Instrument was Activities of Daily Living (ADL) scale, including Basic Activities Daily Living (BADL) and Instrumental Activities of Daily Living (IADL). Living arrangements were significantly associated with BADL, IADL and ADL disability. Married persons living with or without children were more advantaged on all three dimensions of functional disability. Unmarried older adults living with children only had the worst functional status, even after controlling for background, social support, income and health status variables (compared with the unmarried living alone, ß for BADL: -1.262, ß for IADL: -2.112, ß for ADL: -3.388; compared with the married living with children only, ß for BADL: -1.166, ß for IADL: -2.723, ß for ADL: -3.902). In addition, older adults without difficulty in receiving emotional support, in excellent health and with advanced age had significantly better BADL, IADL and ADL function. However, a statistically significant association between physical assistance and functional disability was not found. Functional disabilities vary by living arrangements with different patterns and other factors. Our results highlight the association of unmarried elders living with children only and functioning decline comparing with other types. Our study implies policy makers should pay closer attention to unmarried elders living with children in community. Community service especially emotional support such as psychological counseling is important social support and should be improved.
    Full-text · Article · Jan 2013 · PLoS ONE
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    ABSTRACT: The initiators caspase-9 (CASP9) and caspase-10 (CASP10) are two key controllers of apoptosis and play important roles in carcinogenesis. This study aims to explore the association between CASPs gene polymorphisms and colorectal cancer (CRC) susceptibility in a population-based study. A two-stage designed population-based case-control study was carried out, including a testing set with 300 cases and 296 controls and a validation set with 206 cases and 845 controls. A total of eight tag selected single nucleotide polymorphisms (SNPs) in CASP9 and CASP10 were chosen based on HapMap and the National Center of Biotechnology Information (NCBI) datasets and genotyped by restriction fragment length polymorphism (RFLP) assay. Multivariate logistic regression models were applied to evaluate the association of SNPs with CRC risk. In the first stage, from eight tag SNPs, three polymorphisms rs4646077 (odds ratio (OR)(AA+AG): 0.654, 95% confidence interval (CI): 0.406-1.055; P=0.082), rs4233532 (OR(CC): 1.667, 95% CI: 0.967-2.876; OR(CT): 1.435, 95% CI: 0.998-2.063; P=0.077), and rs2881930 (OR(CC): 0.263, 95% CI: 0.095-0.728, P=0.036) showed possible association with CRC risk. However, none of the three SNPs, rs4646077 (OR(AA+AG): 1.233, 95% CI: 0.903-1.683), rs4233532 (OR(CC): 0.892, 95% CI: 0.640-1.243; OR(CT): 1.134, 95% CI: 0.897-1.433), and rs2881930 (OR(CC): 1.096, 95% CI: 0.620-1.938; OR(CT): 1.009, 95% CI: 0.801-1.271), remained significant with CRC risk in the validation set, even after stratification for different tumor locations (colon or rectum). In addition, never tea drinking was associated with a significantly increased risk of CRC in testing set together with validation set (OR: 1.755, 95% CI: 1.319-2.334). Our results found that polymorphisms of CASP9 and CASP10 genes may not contribute to CRC risk in Chinese population and thereby the large-scale case-control studies might be in consideration. In addition, tea drinking was a protective factor for CRC.
    Full-text · Article · Jan 2013 · Journal of Zhejiang University SCIENCE B
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    ABSTRACT: Hydrogen donor visbreaking and conventional visbreaking processes of vacuum residue of Venezuelan synthetic crude oil were investigated in an autoclave. Phase changes of the two reaction systems were observed by a microscope during the thermal conversion. The stabilities of two kinds of visbroken oil were characterized and their SARA group compositions were analyzed. The results show that amorphous micro-particles' formation, growth and aggregation can be observed clearly by the microscope with the increasing of time at 425°C. Resins and asphaltenes contents in two visbroken oils are both decrease. Compared to conventional visbreaking process, hydrogen donor in hydrogen donor visbreaking process can inhibit the growth of amorphous micro-particles to postpone the phase separation. Moreover, hydrogen donor can inhibit the coke formation and improve the stability of visbroken oil.
    No preview · Article · Nov 2012 · Journal of Fuel Chemistry and Technology
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    ABSTRACT: SARA fractions (i.e., saturates, aromatics, resins, and asphaltenes) were prepared from vacuum residues of a Venezuelan crude oil and a Chinese Liaohe crude oil. Thermal performance of the fractions and their blends, plus interactions between the fractions, was then quantitatively studied by thermogravimetric analysis (TGA), derivative thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Results indicated that the thermal processes of saturates, aromatics, and resins are endothermic to varying degrees because of thermal cracking. In contrast, both asphaltenes show exothermic behavior throughout the process. Then, it was found that there is a good linear dependency of enthalpy of fractions and blends upon the coke yield. The thermodynamic characteristic of a feedstock would change from endothermic to exothermic when its coke yield rises to some point, which is 49.1 wt % in this study. Furthermore, the difference in the coke yields and enthalpies between theoretical and experimental values revealed that synergic interactions between fractions could change the underlying chemical reaction pathway and, thus, in turn, influence the enthalpy of the thermal process. Proper selection of the blending feedstocks might therefore reduce energy consumption in coking processes in addition to inhibiting coke formation.
    No preview · Article · Oct 2012 · Energy & Fuels
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    Kun Chen · Zongxian Wang · He Liu · Aijun Guo
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    ABSTRACT: The heat in heavy oil pyrolysis process is a quantity of interest in the design of thermal process equipments and the calculation of energy balance in refineries. Thus, enthalpy of reaction and enthalpy of vaporization in the pyrolysis of four heavy oils: DQVR (Daqing vacuum residue), KRVR (Karamay vacuum residue), LHVR (Liaohe vacuum residue) and VNVR (Venezuela vacuum residue), have been quantitatively studied by a combination of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), plus microreactor experiments. As sample became heavier, the temperature range of pyrolysis process increased from 172 to 200 °C and enthalpies of reaction decreased, which were determined to be − 1070, − 570, − 489 and − 393 J/g for DQVR, KRVR, LHVR and VNVR, respectively. The enthalpies of reaction at various conditions showed a linear trend with respect to the final coke yield in the thermal analysis. Enthalpies of vaporization in the thermal analysis process were calculated to be 188, 181, 161 and 128 J/g, for DQVR, KRVR, LHVR and VNVR, respectively. The contribution of vaporization to the overall pyrolysis process varied between 0.12 and 0.19. A method to quantify the enthalpy of cracking and that of condensation was tentatively developed by using extrapolation.
    Full-text · Article · Jul 2012 · Fuel Processing Technology
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    ABSTRACT: This study aims to explore the associations of polymorphisms in tachykinin, precursor 1 (TAC1), tachykinin receptor 1 (TACR1), and tachykinin receptor 2 (TACR2) genes and their interactions with the risk of colorectal cancer (CRC) among Chinese population. A population-based case-control study which included 394 cases and 393 cancer-free controls was carried out. A total of 19 tagSNPs in the three genes were chosen based on HapMap and NCBI datasets and genotyped by SNPshot assay. Multiple logistic regression models were applied to evaluate the associations of SNPs with CRC after adjustment for potential covariates. Furthermore, generalized multifactor dimensionality reduction (GMDR) method was used to test the interactive effect among three genes on CRC. Compared with those carrying rs3755457 CC/CT or rs12477554 TT/CT genotype, individuals carrying homozygous variants had higher risk of colorectal cancer (adjusted OR = 1.80, 95 % CI = 1.03-3.13, P = 0.039 for rs3755457; adjusted OR = 1.73, 95 % CI = 1.07-2.79, P = 0.024 for rs12477554). As for rs10198644, GG genotype was associated with a 1.72-fold (95 % CI = 0.37-0.88) decreased risk when compared with the common CC genotype. Moreover, the GMDR analysis indicated that the best interactive model included five polymorphisms: rs2072100 (TAC1), rs10198644 (TACR1), rs2193409 (TACR1), rs3771810 (TACR1), and rs4644560 (TACR2). Our study suggests that tachykinins pathway genes may participate in the development of CRC and the potential interactions among the three genes on CRC may exist, which has to be confirmed in future larger studies.
    No preview · Article · Jun 2012 · International Journal of Colorectal Disease
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    ABSTRACT: Enthalpy of pyrolysis and its variation in the pyrolysis process of four heavy oils: Daqing vacuum residue (DQVR), Karamay vacuum residue (KRVR), Liaohe vacuum residue (LHVR), and Venezuela vacuum residue (VNVR), have been quantitatively studied by differential scanning calorimetry associated with thermogravimetry. The results indicate that overall enthalpies at different heating rates show a linear trend with respect to the final coke yields in the thermal analysis. Classical kinetic method (Friedman method) is used to further analyze pyrolysis enthalpy variation in the pyrolysis process and determine the thermokinetic parameters. The main stage of thermal reaction (conversion ranges from 0.1 to 0.9) could be described by 1.5 order reaction model for four heavy oils. The mean activation energies determined by Friedman method are 216.3, 194.9, 173.9, and 168.7 kJ mol−1 for DQVR, KRVR, LHVR, and VNVR, respectively. It means that endothermic enthalpy of pyrolysis in the thermal process of VNVR is easier to change compared with other oil sample cases. For the sake of simplification of kinetic treatment, Sharp method is tentatively used to perform kinetic analysis. The comparison between results from two methods indicates that activation energies from Sharp method are valid to a certain degree under the condition that the mechanism of thermal process is properly chosen although isoconversional method (Friedman method) is recommended and thought to be the better way.
    No preview · Article · Jun 2012 · Journal of Thermal Analysis and Calorimetry

Publication Stats

49 Citations
34.08 Total Impact Points


  • 2012-2015
    • University of Petroleum (East China)
      Tsingtao, Shandong Sheng, China
  • 2012-2013
    • Zhejiang University
      • • School of Medicine
      • • School of Public Health
      Hang-hsien, Zhejiang Sheng, China