Performance evaluation of gasifier based on energy analysis /

Abstract

Gasification processes have received significant attention in recent years due to increasing world energy needs and growing environmental considerations. Gasification is a relatively environment friendly process but has low thermodynamic efficiency. Such thermodynamic inefficiencies and irreversibilities reduce the overall plant efficiency. Exergy analysis ― a concept derived from the second law of thermodynamics ― makes it possible to improve overall process efficiency by detecting and reducing thermodynamic irreversibilities in a process. In this research project, an entrained-flow coal gasifier has been simulated using Aspen Plus® process simulator. First, a steady-state simulation model is developed and fine-tuned to match available experimental data. The results of this reference simulation are used as input for exergy analysis of the gasifier. The study then focuses on a systematic investigation of the influence of feedstock composition and operating conditions (including oxygen-to-coal and steam-to-coal ratios) on overall exergy efficiency of the gasifier. The outcome of this detailed analysis is a set of recommendations for choosing optimum gasification conditions for a given coal typ