Synthesis of biodiesel using ZrO₂ polycrystalline ceramic foam catalyst in a tubular reactor

With the help of the ceramic foam research efforts and preparation techniques, the Zr02 polycrystalline ceramic foam catalyst was synthesized, and its characteristics, including the crystal structure, the phase composition, the acid-base properties, and the microstructure, were analyzed by XRD, SEM, Py-IR, and BET techniques. The performance of the ZrO₂ polycrystalline ceramic foam catalyst in a tubular reactor was investigated via biodiesel synthesis using S. wilsoniana oil and methanol. The effects of reaction conditions (i.e., reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil) on transesterification efficiency were investigated, and the reaction conditions were optimized using RSM. The optimum reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil were determined to be 290 °C, 10 MPa, and 4:1, respectively. Under this condition, the FAME content in the product oil reached 98.38%. The performance of the ZrO₂ polycrystalline ceramic foam catalyst synthesized in this work for biodiesel synthesis from S. wilsoniana oil with a moisture content of 7.1% and an acid value of 130.697 mg KOH/g was examined, and the FAME content in the product oil was found to be 93% and 97.67%, respectively. The FAME content in the product oil exceeded 97% after five consecutive cycles (12 h per cycle of use) of the catalyst. The proposed catalyst represents a new type of solid catalyst with excellent acid resistance, water resistance, esterification efficiency, and catalytic stability.