Optimisation of Syngas Production from Paper Waste Sludge by Up-draft Gasification: A Response Surface Methodology Approach

Abstract

This research investigated an up-draft gasification system of paper waste sludge (PWS) to generate syngas. Lower heating value (LHV) and cold gas efficiency (CGE) are influenced by PWS moisture content and equivalence ratio (ER). Supply air for gasification by increasing ER reduced LHV due to increased inert gas (N2) content. PWS moisture provides steam for the water-gas shift reaction that increases LHV and CGE. But the moisture of the PWS higher than 15 % significantly reduced the gasification temperature (less than 800 ?), causing the overall gasification efficiency to decrease. According to the response surface methodology (RSM) using Design Expert software, the optimum conditions were predicted that PWS moisture of 11.09 %, ER of 0.104, syngas produced with an LHV of 10.48 MJ/kg, and a CGE of 67.55 %. Experimenting with a real model has similar results with small differences compared to the RSM model in the same conditions. Syngas from the real model has an LHV of 10.22 ± 0.24 MJ/kg and a CGE of 65.68 ± 1.02 %. PWS gasification under optimal conditions is an effective PWS treatment method that not only solves PWS but can also generate energy in the form of syngas.