Optimization of kerosene from a one-step catalytic hydrogenation of castor oil over Pt-La/SAPO-11 by response surface methodology

Abstract

A one-step continuous catalyzed hydrogenation preparation of bioaviation kerosene was prepared from castor oil with a molecular probe in a high-pressure microfixed bed. The catalyst was Pt-La/SAPO-11, which was synthesized by the impregnation of Pt, as the active metal component, and metal auxiliaries. The effect of adding metal auxiliaries into the bifunctional metal was evaluated by XRD, XRF, BET, TEM, and Py-IR techniques, and it was confirmed that the hydrodeoxygenation performance, the selectivity of C8–C16 alkanes, the selectivity of C8–C16 isoalkanes, and the selectivity of C8–C16 arenes were all improved. Combined with a Box-Behnken central composite design, the reaction temperature, pressure, liquid hourly space velocity (LHSV), and hydrogen/oil ratio (hydrogen volume/castor oil volume) were selected as the four critical factors for the three levels of selectivity. The response surface method (RSM) was selected to establish a mathematical model with a second-order quadratic equation and optimize the process parameters for enhancing the selectivity of C8–C16 alkanes. The optimization conditions of the four process parameters were found to be a temperature of 405 °C, a pressure of 3.9 MPa, an LHSV of 0.93 h−1, and a hydrogen/oil ratio of 990 NmL mL−1. Three verification experiments showed that the selectivity of C8–C16 alkanes was 58.76%.