Optimizing catalysts and reaction conditions for transalkylation as well as hydrodeoxygenation reactions in a hydropyrolysis process while minimizing demethylation reactions may improve carbon yield and energy recovery in the liquid product. Pyrolysis vapor model compound hydrodeoxygenation reactions were investigated in a fixed bed reactor at 350–450 °C, 1.7–15 bar (10–200 psig), with 14–60 mol % hydrogen in the feed gas mixture to determine reaction pathways under a range of reaction conditions. Anisole hydrodeoxygenation reaction pathways in the gas phase were studied over a commercially available Ni-based hydrotreating catalyst, whereas guaiacol hydrodeoxygenation reaction pathways were studied over two different commercially available Ni-based hydrotreating catalysts, a Fe-based catalyst, and a zeolite-based catalyst using online mass spectrometry analysis. Both Ni-based catalysts exhibited greater hydrodeoxygenation activity than the Fe-based and zeolite-based catalysts. Guaiacol conversion over each Ni-based catalyst reached 99.5 and 99.6%, whereas conversion over Fe-based and zeolite-based catalysts reached 27.0 and 22.7%, respectively, under the same reaction conditions. Experimental data from online mass spectrometry indicate that anisole and guaiacol undergo transalkylation and demethylation reactions followed by hydrodeoxygenation reactions over each catalyst tested.
Anisole and guaiacol hydrodeoxygenation reaction pathways over selected catalysts
Peters, J., Carpenter III, J., & Dayton, D. (2015). Anisole and guaiacol hydrodeoxygenation reaction pathways over selected catalysts. Energy & Fuels, 29(2), 909-916. https://doi.org/10.1021/ef502551p