Abstract:
Preparation of nano Cu/ZnO catalyst by ultrasonic spray pyrolysis (USP) for LPG production was examined. Hollow spherical particles were obtained using an aqueous solution of Cu(NO3)3.6H2O and Zn(NO3)3.3H2O at different concentration of 0.05, 0.1 and 0.5 molar under the pyrolysis temperature of 600, 700 and 800°C. Mists of the solution were generated from the starting solution with ultrasonic vibrators at frequency of ~1.7 MHz. The physicochemical properties of catalysts were characterized by X-ray diffraction, Temperature-programmed reduction, Scanning electron microscope, Nitrogen adsorption-desorption and Energy dispersive X-ray spectrometer. The results showed that increasing in precursor concentration resulted in a large particle and particles size distributed in a range of 0.63-1.21 micron. Particles prepared at pyrolysis temperature 700°C exhibited homogeneous in size and shape compared to other temperature. The catalytic activity of nano Cu/ZnO-Pd-β catalysts was performed in a fixed-bed reactor for synthesizing LPG. The reaction took place at 260°C, 3.0 MPa, and the ratio of H2:CO:CO2:Ar = 60:32:5:3. All the products from the reactor were in gaseous state, and analyzed by online gas chromatography. The results showed that CO conversion was high but decreased rapidly with increasing reaction time. Cu/ZnO catalyst prepared by co-precipitation found that CO conversion was 31.18 % with selectivity of LPG was 56.00 %. While Cu/ZnO catalyst prepared at 0.1 M 800°C by ultrasonic spray pyrolysis found that CO conversion was 6.27 % with selectivity of LPG was 61.65 %.