Maya asphaltene

Zajac GW, Sethi NK, Joseph JT (1997) Molecular imaging of Maya asphaltenes by scanning tunneling microscopy. 1997 ACS Spring Meeting, Fuel, abstract No 69... 

Douda, J., Alvarez, R., Navarrete, J. 2008. Characterization of maya asphaltene and maltene by means of pyrolysis application. Energy Fuels 22 2619-2628. 

Douda, J., Llanos, M.E., Alvarez, R., Lopez, C., Montoya, J.A. 2004. Pyrolysis applied to the study of a maya asphaltene. /. Anal. Appl. Pyrolysis 71 601-612. 

Callejas, M. A., and Martmez, M. T., Hydroprocessing of a Maya Residue. 1. Intrinsic Kinetics of Asphaltene Removal Reactions. Energy Fuels, 2000. 14 pp. 1304—1308. 

Fractionation by solubility is used to isolate asphaltenes from maltenes, and the standard method (ASTM-3279-97) has been used in this work. Crude petroleum is mixed with 40 volumes of heptane, heated, stirred, and left to cool. The asphaltenes form a precipitate that can be removed by filtration. Normal practice is to clean the asphaltene fraction by Soxhlet in heptane. The proportions of asphaltene in crude petroleums vary widely, from less than 0.1% in the best crudes to over 10% in the heavy crudes. In general, the heavy crudes such as Maya are of most interest. The solubility of petroleum asphaltene in NMP is of interest since the NMP-insoluble material has no fluorescence [61] and was initially assumed to be aliphatic. However, it has UV absorbance and must be aromatic [62]. The separation into NMP soluble and insoluble was achieved for several asphaltenes. A Kuwaiti asphaltene was separated into NMP-soluble and -insoluble fractions [63]. Seven crude oils were fractionated into heptane solubles and asphaltenes for comparison with an asphaltene from a heavy oil [64]. 

The Maya crude oil and asphaltene fractions have been studied [75,77,91]. A typical elemental analysis of the Maya crude is listed in Table 33.1, and the fraction weights are shown in Table 33.2. Figure 33.4A shows the mass spectra of the maltene fraction at different levels of LP spectra 1 and 2 barely exceed the ionization threshold, and spectra 4 and 5 show excessive LP with... 

FIGURE 33.6 Maya fractions considered to represent probably the best mass spectra with (laser power%/HMA voltage kV) 1, heptane solubles (50%/9) 2, asphaltenes (50%/7.5) 3, NMP-soluble asphaltenes (40%/7.5) 4, NMP-insoluble asphaltenes (40%/8). Data from Morgan [75] and Herod et al. [77]. 

Klein et al. " investigated the pyrolysis kinetics of resids, isolated asphaltenes and maltenes from Hondo, Arabian heavy, Arabian light, and Maya oils. At 400°C and 425°C, isolated asphaltenes reacted selectively to form maltenes. At higher temperatures (450°C), asphaltenes reacted... 

Trejo, F., Ancheyta J., (2007). Characterization of Asphaltene Fractions from Hydrotreated Maya Crude Oil. Ind. Eng. Chem. Res., 46, 7571-7579 F. Trejo F. Ancheyta J. Morgan T. J. , Herod A. A., Kandiyoti R., (2007). Characterization of Asphaltenes from Hydrotreated Products by SEC, LDMS, MALDI, NMR, and XRD. Energy Fuels 2007,21,2121-2128... 

Zhao, B. Shaw, J.S. (2007). Composition and Size Distribution of Coherent Nanostructures in Athabasca Bitumen and Maya Crude Oil. Energy Fuels. Vol.21, pp. 2795-2804 Zeng, H. Song, Y.Q. Johnson, D.L. Mullins, O.C. (2009). Critical Nanoaggregate Concentration of Asphaltenes by Low Frequency Conductivity. Energy Fuels, Vol.23, pp. 1201-1208... 

Trasobares et al. (1998) analyzed the association of CCR conversion with feed properties such as asphaltenes content, hydrogen content, H/C atomic ratio, and residue content (350 C+) in the catalytic hydroprocessing of a Maya residue. They found that CCR was linearly correlated with all the parameters. Gas yield was also found to be linearly dependent on CCR conversion. 

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