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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 °C), 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. [ABSTRACT FROM AUTHOR]

In this study, the gasification of rice husk in a downdraft process is simulated by Aspen Plus software to predict an appropriate operation condition for designing small-scale equipment. Gibbs models of the reactions occurring in the process are applied for the simulation while tuning the equivalence ratio (ER) to forecast the syngas' compositions. Based on the analysis, ER value of 0.096 is selected to generate a syngas mixture consisting of CO (43.26 mol%), CH4 (0.09 mol%), and H2 (33.87 mol%), corresponding to the optimal calorific value of 8.92 MJ/kg and efficiency of 86.98 %. A real experiment is performed with the small-scale gasifier to evaluate the results obtained from the simulation. The pilot results show that not only the input air flow rate but other confounding factors also affect the combustion efficiency at some degree, which is compatible with the simulation model. The total energy value acquired from the conversion of 5.0 kg of dry rice husk was 86.82 MJ, while the energy value of the syngas obtained was 44.42 MJ syngas. [ABSTRACT FROM AUTHOR]