Two-Step Gasification of Cattle Manure for Hydrogen-Rich Gas Production: Effect of Gasification Temperature, Steam Flow Rate, and Catalysts

Abstract

Highlights Steam gasification parameters of cattle manure char were optimized. Effects of slow heating and fast heating modes on char gasification were analyzed. 1.92 m3/kg syngas yield and 88.72% C-conversion efficiency were obtained at 850 °C, with fast heating, 1.66 g/min of steam flow rate, and K2CO3 catalyst. Abstract. This study investigated the hydrogen-rich gas production from cattle manure char by steam gasification. The characteristics of char were studied by proximate analysis, ultimate analysis, thermogravimetric analysis, and XRD analysis. The effects of temperature, heating mode, steam flow rate, and catalyst on syngas yield, hydrogen yield, gas composition, heating value, and carbon conversion efficiency were explored. The results showed that the fixed carbon content in cattle manure char was 34.46%, an increase of 2.24 times compared with that of cattle manure, and the cattle manure char had a high fixed carbon content and thermal stability. The steam gasification indicated that the high temperature and fast heating could obtain high syngas and hydrogen yields. The steam flow rate played an important role in the char and steam reforming reactions. The SiO2 and ash catalysts had an inhibitory effect on the steam gasification of char. However, the K2CO3 catalyst improved the syngas and hydrogen yields. The optimal parameters in this study were 850 °C, fast heating, 1.66 g/min of steam flow rate, and K2CO3 catalyst. By comparison, the syngas and hydrogen production of char were better than those of biomass. As a result, the steam gasification of char was a promising method for producing hydrogen-rich gas. Keywords: Catalysts, Cattle Manure Char, Hydrogen, Steam Flow Rate, Steam Gasification.