a2=r()+(） dⅣ=F:-Fo d We can obtaina general mass balance equation that describes the change of y with time 命=0-0+0-8++号鲁。 ( ) dt y dV dt dy V dt d Vy  +      = ( ) Fi Fo dt dV = − g o o g i i y y o i i y V Q y V Q y r V F y y V F dt dy = ( − ) + ( − ) + + , − , We can obtain a general mass balance equation that describes the change of y with time