Gasification of Sewage Sludge: Thermodynamic Equilibrium Modeling

Abstract

The aim of the article is to show the effects of the main gasifier operating parameters, such as temperature, equivalence ratio, steam-to-fuel ratio, and gasification medium selection, on the gasification performance of sewage sludge. Using the developed one-dimensional mathematical thermodynamic equilibrium model for plasma and fluidized bed gasification, a comprehensive parametric study is established. The model is based on the principle of the minimum of the Gibbs function and uses only the ultimate and proximate analysis data as input to the model. The output of the model gives the equilibrium composition of the gasses produced. When comparing different gasification media, gasification with water steam gives a higher yield of H2 and CO in the syngas produced. Further comparison of the two gasification processes in terms of energy consumption is shown. The collected results can be useful in further analysis of the gasification processes, such as energy and exergy analysis and kinetics.