CFD based combustion model for sewage sludge gasification in a fluidized bed

Abstract

Gasification is one potential way to use sewage sludge as renewable energy and solve the environmental problems caused by the huge amount of sewage sludge. In this paper, a three-dimensional Computational Fluid Dynamics (CFD) model has been developed to simulate the sewage sludge gasification process in a fluidized bed. The model describes the complex physical and chemical phenomena in the gasifier including turbulent flow, heat and mass transfer, and chemical reactions. The model is based on the Eulerian-Lagrangian concept using the nonpremixed combustion modeling approach. In terms of the CFD software FLUENT, which represents a powerful tool for gasifier analysis, the simulations provide detailed information on the gas products and temperature distribution in the gasifier. The model sensitivity is analyzed by performing the model in a laboratory-scale fluidized bed in the literature, and the model validation is carried out by comparing with experimental data from the literature. Results show that reasonably good agreement was achieved. Effects of temperature and Equivalence Ratio (ER) on the quality of product syngas (H 2 + CO) are also studied.

Perspective of Waste to Energy and Fuel with Negative Emission Potential: Smart Environmental and Techno-economic Analysis

“…For combustion-based conversion, CFD models study factors such as feedstock properties, gas emissions, operating parameters, and combustion efficiency . In gasification processes, CFD models assess experimental conditions for gasification reactors, including the feedstock particle size, steam and air flow rates, residence time, temperature, pressure, syngas composition, temperature distribution, turbulent flow, heat and mass transfer, and chemical reactions . However, there is relatively less CFD modeling research specifically focused on wet-waste pyrolysis and wet-waste gasification.…”