Preparation of Ni-based steel slag catalyst by impregnation method for sludge steam gasification

Abstract

In this study, a nickel (Ni)-based catalyst was loaded onto steel slag that was rich in metal oxides using impregnation method. The effects of the catalyst on hydrogen-rich gas produced using sludge steam gasification were discussed. Under the conditions of 900 ℃, steam flowrate of 1.5 g min−1 and 20% Ni-based loading rate, the gas and H2 yield reached 0.78 Nm3 kg−1 and 15.72 mol kg−1. At this time, the volume fraction of H2 was as high as 45.096%. Compared with the raw sludge gasification without Ni-based catalyst, the gas and H2 yield were increased by 39.22% and 60.15% respectively. However, excessive flowrate of steam (≥1.5 g min−1) and excessive rate of loading of Ni-based (≥25%) catalyst would lead to a decrease in the production of gas. In addition, the impregnation method could effectively disperse NiO particles on the surface of the support, increasing the ratio of active sites on the surface of catalyst and improving the catalytic activity. These characteristics indicated that the Ni-based steel slag catalysts prepared by the impregnation method had high application potential in the process of sludge steam gasification, and provided a novel idea for solid wastes recycling.