Control of Solids Flow Through the Orifice in a Downcomer

摘要

Solids flowrate in non-fluidized downcomers may be controlled by throttling the flow using a slide valve at the base of the downcomer or by changing the upward gas flowrate. Both mechanisms eventually lead to an unstable operating condition. This paper presents a mechanistic explanation and a quantitative method for predicting the transition point from stable to unstable flow conditions.