A research has been made on the flow characteristics of an improved U-valve in the CFB combined with a coal pyrolysis reactor.Effects of the single gas

double gases and horizontal orifice on the circulating rates have been studied.The research shows that

when fluidized gas is used only

it had little effect on the quantity of returning solids

and that the effect of loosed gas is significant.Horizontal opening has distinct effect on the circulating rate only when the loosed gas is larger;the appropriate horizontal opening is corresponding to the gases quantity.The combining of the arced gas distributor and the gases regulating could eliminate the fluidized dead zone in the U-valve effectively.