Performance of Aluminophosphate Molecular Sieve Catalysts for the Production of Hydrocarbons from Wood-Derived and Vegetable Oils

Abstract

A wood-derived oil and canola oil (termed bio-oils) were converted catalytically over aluminophosphate catalysts, namely, SAPO-5, SAPO-11 and MgAPO-36. The catalysts were prepared and then characterized using BET surface area, pore size, X-ray powder diffraction, ammonia temperature-programmed adsorption and desorption, and NMR measurements. The test runs were performed in a fixed bed microreactor which was operated at 3.6 weight hourly space velocity (WHSV) and temperature ranges of 330-410 °C for wood-derived oil (WDO) and 375-550 °C for canola oil. The objective was to investigate the potential for the production of both liquid and gaseous hydrocarbon products from the conversion of bio-oils using aluminophosphate catalysts. With WDO, between 12 and 23 wt % of an organic liquid product (OLP) was obtained which contained an optimum of 61.5, 56.8, and 57.0 wt % (for SAPO-5, SAPO-11, and MgAPO-36, respectively) liquid hydrocarbons. All three catalysts were selective for both aromatic and aliphatic hydrocarbons in comparable proportions. With canola oil, between 12 and 48 wt % OLP was obtained. The optimum yields of hydrocarbons were 65.8, 51.1, and 45.3 wt % of OLP for SAPO-5, SAPO-11, and MgAPO-36, respectively. SAPO-5 and SAPO-11 were highly selective for aromatic hydrocarbons. On the other hand, MgAPO-36 produced high fractions of aliphatic hydrocarbons at temperatures below 450 °C and high aromatic hydrocarbons at temperatures above 450 °C. Furthermore, 8-17 and 5-63 wt % gas was produced with WDO and canola oil, respectively. The gas composition consisted mostly of C 1 -C 4 hydrocarbons. The results showed that the conversion of bio-oils to hydrocarbons with aluminophosphate catalyst was low as compared to HZSM-5 catalyst. However, some potential exists for the production of hydrocarbons such as benzene (with WDO) and toluene and xylenes (with canola oil) as well as important gaseous hydrocarbons such as ethylene, propylene, and n-butane.