Catalytic Pyrolysis of Pine Over HZSM-5 with Different Binders

Three HZSM-5 catalysts with different binders (alumina, silica, and clay) were evaluated for upgrading of pine pyrolysis vapors. All catalysts were based on the same HZSM-5 with silica to alumina molar ratio of 30. Experiments in micro-scale analytical Py-GCMS/FID showed that fresh catalysts with silica and clay produced predominantly aromatic hydrocarbons at similar carbon yields. The catalyst with alumina gave lower vapor yields and produced both hydrocarbons and partially deoxygenated products, in particular furans. The catalyst with alumina also gave higher coke yields and exhibited faster deactivation than the catalysts with clay and silica binders. The low hydrocarbon yields and coke formation were attributed to the acidic sites provided by alumina and blocking of the zeolite sites. The catalysts with silica and clay as binders were further tested in a 2-inch fluidized bed system for ex situ catalytic pyrolysis of pine. Similar oils were produced over both catalysts with carbon yields of approximately 23 % and oxygen contents of 20–21 %.