Low-temperature catalytic gasification of sewage sludge-derived volatiles to produce clean H2-rich syngas over a nickel loaded on lignite char

Abstract

Catalytic gasification (CG) of sewage sludge-derived volatiles (SSDVs) was investigated over a prepared nickel loaded on Loy Yong lignite char (Ni/LYLC) in a two-stage fixed-bed reactor to understand the effects of the catalyst, temperature, and steam on the gas yields and nitrogen transformations. Non-catalytic thermal decomposition of SSDVs below 650 °C is not effective for decomposing the tar and converting the volatile nitrogen species (VNSs) to N2. Ni/LYLC proved to be quite active not only for tar reduction, but also for the conversion of VNSs to N2 at 650 °C. CG of SSDVs over Ni/LYLC produced significant amount of clean H2-rich syngas. CG above 650 °C results in the increase of nickel crystallite size and the deactivation of Ni/LYLC for tar decomposition. The study revealed the possibility of using Ni/LYLC as a potential catalyst for low-temperature CG of sewage sludge to produce clean H2-rich syngas.