Synthesis gas production from catalytic gasification of waste biomass using nickel-loaded brown coal char

This paper presents an experimental research concerning the catalytic gasification of waste biomass to synthesis gas using Ni-loaded brown coal char (Ni/BCC). The attention is focused on the catalytic conditions for enhancing the synthesis gas production, improving its composition and extending the catalyst lifetime. The aim is achieved by means of the characterization of Ni/BCC and the product gas analysis, through gasification experiments of a woody biomass and an animal-waste-derived biomass both in a fixed bed reactor and a fluidized bed reactor at various catalytic temperatures and steam/biomass–carbon (S/C) ratios. Effects of the pyrolysis temperature and the steam treatment on the nickel crystallite size are analyzed and used as the reference of choosing optimum gasification conditions. With brown coal char as support material, Ni/BCC is found as an excellent catalyst even at low temperature of about 650 °C and shows a good resistance ability of coke formation, compared to non-catalyst and Ni/Al2O3. More than 25 h continuous operation is also performed in a 1 kg/h Internally Circulating Fluidized-bed Gasifier (ICFG) to assess the lifetime of Ni/BCC. Smaller S/C ratio at the appropriate temperature is suggested to lower the coal char gasification, thereby reducing the degradation of the support material.