Energy Fuels 2011, 25, 524–527 Published on Web 11/10/2010
: DOI:10.1021/ef101069m
Production of Light Oil by Oxidative Cracking of Oil Sand Bitumen Using Iron Oxide Catalysts in a Steam Atmosphere† Eri Fumoto,* Shinya Sato, and Toshimasa Takanohashi Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba 305-8569, Japan Received August 13, 2010. Revised Manuscript Received October 24, 2010
Catalytic cracking of Canadian oil sand bitumen was performed using zirconia-alumina-iron oxide catalysts at 450-500 °C in a steam atmosphere. The heavy-oil fraction of bitumen was oxidatively cracked to produce light oil, corresponding to gasoline, kerosene, and gas oil, with a boiling point of 350 °C) converted to light fractions and carbon dioxide after the reaction of bitumen with the Zr-Al(7.0)-FeOx catalyst for 2 h. It was calculated using the following equation: ¼
conversion mole fraction of heavy oil and coke in product 100 1mole fraction of heavy oil in feedstock
ð1Þ The conversion of heavy oil increased with an increasing temperature and W/F and reached a maximum of approximately 60 mol % C when W/F was 3.6 h at 475 and 500 °C. The rate of carbon-carbon bond cleavage was enhanced at higher temperatures, and larger amounts of active oxygen species were generated from steam and effectively reacted with heavy oil using higher W/F and higher temperatures. Figure 4 shows the relationship between the product yields and conversion of heavy oil. Gas oil and gasoline þ kerosene were defined as boiling at 250-350 °C and below 250 °C, respectively. The yield of gas oil, gasoline þ kerosene, gaseous hydrocarbons (C1-C4), and carbon dixoide increased with increasing conversion. On the other hand, the coke yield decreased with increasing conversion (Figure 4d). When conversion was high with higher W/F, large amounts of active oxygen species were generated from steam. The coke formation was suppressed by the reaction of these active oxygen species with heavy oil at high conversion. The reaction of large amounts of active oxygen species and heavy oil
Figure 3. Effects of the reaction temperature and W/F on the conversion of heavy oil. Reaction conditions: T, 450-500 °C; W/F, 0.43.6 h; feedstock, 1-methylnaphthalene solution of bitumen; catalyst, Zr-Al(7.0)-FeOx.
Figure 4. Relationship between the yield and conversion of heavy oil: (a) light oil, (b) gaseous hydrocarbon, (c) carbon dioxide, and (d) coke. Reaction conditions: T, 450-500 °C; W/F, 0.4-3.6 h; feedstock, 1-methylnaphthalene solution of bitumen; catalyst, Zr-Al(7.0)-FeOx.
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Energy Fuels 2011, 25, 524–527
: DOI:10.1021/ef101069m
Fumoto et al.
Table 2. Reaction Conditions Producing the Highest Yields of Light Oil by Cracking Bitumen with the Zr-Al(7.0)-FeOx Catalyst in a Steam Atmospherea conversion temperature (mol % C) (°C) 51.4 58.0 60.3 55.1
450 475 500 500
W/F (h) 3.6 3.6 3.6 2.0
gasc coke light oilb (mol % C) (mol % C) (mol % C) 51.1 50.9 51.0 50.3
8.09 13.8 15.7 12.0
a Feedstock = 1-methylnaphthalene solution of bitumen. oil=gasoline þ kerosene and gas oil. c Gas=CO2 and C1-C4.
0.0 0.0 0.0 0.0 b
Light
Figure 6. Light oil yield after the reaction of bitumen with Zr-Al(17)-FeOx and Zr-Al(7.0)-FeOx catalysts in a steam atmosphere. Reaction conditions: T, 450-500 °C; W/F, 1.2 h; feedstock, 1-methylnaphthalene solution of bitumen.
catalyst containing more alumina [Zr-Al(17)-FeOx] to produce larger amounts of light oil from AR at 450 °C.8 Alumina promoted the cracking of AR; thus, we applied this modified catalyst to the cracking of bitumen at 450 °C. Figures 5 and 6 show the conversion of heavy oil and light oil yields after the reaction of bitumen with the Zr-Al(17)FeOx catalyst for 2 h at 450 °C in a steam atmosphere. Conversion was calculated using eq 1 with the experimental data. The light oil yields (bp
