A transient method to study the pressure drop characteristics of the cyclone in a CFB system

Abstract

A transient method was developed and applied to study the variation of pressure drop characteristics of the cyclone Δ P c used in a circulating fluidized bed (CFB) system with the solid concentration at the inlet C s,in . Experiments were conducted in a CFB apparatus, with a square riser of 0.1 m × 0.1 m in cross-section and 3.2 m in height, and with a smooth riser exit. When the system was in a steady state with a large C s,in , the supply of solid material to the riser was suddenly cut-off while the gas velocity was maintained at a constant. C s,in was derived by the pressure drop measured across the smooth riser exit. Δ P c and C s,in were measured on-line during the transient process. Experimental results showed that Δ P c and C s,in obtained by the transient method were in good agreement with those obtained by the steady state experiments. Furthermore, Δ P c decreased at first with increasing C s,in and then reached at a minimum at the critical C s,in , thereafter it increased with C s,in . The transient method offers an acceptable accurate, cost-effective and productive means to study the Δ P c over a wide range of C s,in .