Kinetics of hydrodeoxygenation of stearic acid using supported nickel catalysts: Effects of supports
Kumar, P; Yenumala, SR; Maity, SK; Shee, D
| HERO ID | 4937073 |
|---|---|
| In Press | No |
| Year | 2014 |
| Title | Kinetics of hydrodeoxygenation of stearic acid using supported nickel catalysts: Effects of supports |
| Authors | Kumar, P; Yenumala, SR; Maity, SK; Shee, D |
| Journal | Applied Catalysis A: General |
| Volume | 471 |
| Page Numbers | 28-38 |
| Abstract | The hydrodeoxygenation of fatty acids derived from vegetable and microalgal oils is a novel process for production of liquid hydrocarbon fuels well-suited with existing internal combustion engines. The hydrodeoxygenation of stearic acid was investigated in a high pressure batch reactor using n-dodecane as solvent over nickel metal catalysts supported on SiO2, gamma-Al2O3, and HZSM-5 in the temperature range of 533-563 K. Several supported nickel oxide catalysts with nickel loading up to 25 wt.% were prepared by incipient wetness impregnation method and reduced using hydrogen. The catalysts were then characterized by BET, TPR, H-2 pulse chemisorption, TPD, XRD, and ICP-AES. Characterization studies revealed that only dispersed nickel oxide was present up to 15 wt.% nickel loading on gamma-Al2O3. The acidity of the supports depends on nickel loading of oxidized catalysts and increases with increasing nickel loading up to 15 wt.%. n-Pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and I-octadecanol were identified as products of hydrodeoxygenation of stearic acid with n-heptadecane being primary product. The catalytic activity and selectivity to products for hydrodeoxygenation of stearic acid depends strongly on acidity of the supports. The maximum selectivity to n-heptadecane was observed with nickel supported gamma-Al2O3 catalyst. A suitable reaction mechanism of hydrodeoxygenation of stearic acid was delineated based on products distribution. The conversion of stearic acid was increased with increasing reaction time, nickel loading on gamma-Al2O3, temperature, and catalyst loading. Complete conversion of stearic acid was accomplished with more than 80% selectivity to n-heptadecane at reasonable reaction temperature of 563 K after 240 min of reaction using 15 wt.% Ni/gamma-Al2O3 catalyst. An empirical kinetic model was also developed to correlate the experimental data. (C) 2013 Elsevier B.V. All rights reserved. |
| Doi | 10.1016/j.apcata.2013.11.021 |
| Wosid | WOS:000331481600004 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Keyword | Hydrodeoxygenation; Stearic acid; Green diesel; Ni/gamma-Al2O3; Modeling |