TWO-STAGE FLASH PERFORMANCE o How can chemical engineers improve on the single stage flash? Answer: Try two stages. Overall Separation Factor sf =sFa= a So sF OveraLL = a. 2 Since ai>l, this is an improvement in the separation factor Overall Fractional Recovery of component lboth stages are operated at the same s, then FR OVERALL FR. FR.= FR2< FR So the overall recovery factor is lower for two stages than for one. 0/6/99 Equilibrium Staged separations0/6/99 Equilibrium Staged Separations 7 TWO-STAGE FLASH PERFORMANCE u How can chemical engineers improve on the single - stage flash? Answer: Try two stages. u Overall Separation Factor SF1jk = SF2jk = a jk So SFOVERALLij = a ik 2 Since a ij > 1, this is an improvement in the separation factor. u Overall Fractional Recovery of component j If both stages are operated at the same Sj , then FROVERALLj = FR1j FR2j = FRj 2 < FRj So the overall recovery factor is lower for two stages than for one