On the scaling-up of a two-stage air blown entrained flow coal gasifier

A two-stage air blown entrained flow gasifier is being developed in Japan f or the IGCC process. However, its scale-up up faces significant difficultie s because of ash/slag deposition problems. The ash/slag deposition in the g asifier depends on both the ash properties and entrainment produced by the swirling gas flow. Therefore, the flow hydrodynamics are critical issues fo r the control of the ash behavior. In this paper, a comprehensive simulatio n model is used to examine the effects of the gasifier geometry and jet con figuration on the flow hydrodynamics in order to control the ash deposition on the gasifier walls. A swirl number for the multi-stage injection swirli ng gas flow is defined and proved to be the most important hydrodynamic sca ling law for the entrained flow gasifier.