Single- and double-stage catalytic preferential CO oxidation in H 2-rich stream over an α-Fe 2O 3-promoted CuO–CeO 2 catalyst

Abstract

Single- and double-stage catalytic preferential CO oxidation (CO-PrOx) over-Fe 2O 3-promoted CuO–CeO 2 in a H 2-rich stream has been investigated in this work. The catalyst was prepared by the urea-nitrate combustion method and was characterized by X-ray diffractometer (XRD), X-ray fluorescence (XRF), Brunauer–Emmet–Teller (BET), transmission electron microscope (TEM), and scanning electron microscope (SEM). The catalytic activity tests were carried out in the temperature range of 50–225 °C under atmospheric pressure. The results of the single-stage reaction indicated that complete CO oxidation was obtained when operating at a O 2/CO ratio of 1.5, W/ F ratio of 0.36 g s/cm 3, and at a reaction temperature of 175 °C. At these conditions, H 2 consumption in the oxidation was estimated at 58.4%. Applying the same conditions to the double-stage reaction, complete CO oxidation was found and H 2 consumption in the oxidation was reduced about 4.9%. When decreasing the double-stage reaction temperature to 150 °C, the results elucidated that CO could be converted to CO 2 completely while H 2 consumption in the oxidation was further reduced to 33.5%. A temperature blocking 2 2 factorial design has been used to describe the importance of the factors influencing the catalytic activity. The factorial design was according to the experimental results. When adding CO 2 and H 2O in feed, reduction of CO conversion for single- and double-stage reaction is obtained due to a blocking of CO 2 and H 2O at a catalytic active site. Comparing CO conversion obtained when operating with/without CO 2 and H 2O in feed for single- and double-stage reaction, less reduction is achieved when operating in double-stage reaction.