Influence of pressure on fluidized bed gasifier: Specific coal throughput and particle behavior

Abstract

In this work, the influence of pressure on specific coal throughput and particle behavior was investigated. Firstly, mono-gasification of Jincheng anthracite (JCA) and meat and bone meal (MBM) and co-gasification of JCA and MBM were performed in pressurized fluidized bed gasifier pilot plant with a pressure of 0.1–2.6 MPa and a temperature of 900–1050 °C (mono-gasification of MBM at about 750 °C). It was found that the specific coal throughput is approximately directly proportional to the pressure to the power of 0.6–0.75 and co-gasification leads to successful thermochemical conversion of JCA as opposed to mono-gasification. Furthermore, a series of experiments, in a Pseudo-2D cold mode of a pressurized fluidized bed gasifier using an optic fiber probe system, have been performed to investigate the effects of pressure, fluidizing-gas velocity and static bed height on the particle behavior. The bed material used in this study was polystyrene having average diameter of 1.32 mm. It was found that the effect of pressure on vertical local-particle velocities (Vp) at low bed height (LBH) can be ignored at identical excess fluidizing-gas velocity while Vp at high bed height (HBH) decrease slightly with pressure in the lower pressure range (evidently below approximately 1.2 MPa) and increase thereafter. The effects of the fluidizing-gas velocity on Vp at LBH and HBH are also different. However, the effects of static bed height on Vp both at LBH and HBH are the same under pressure.