For 10 points, name this ratio which measures how much liquid returns to the column during distillation.
A normalized form of this quantity is represented by X in the expression "1 + 54.4X, over 11 + 117.2X", which is Molokanov's correlation. Lord Rayleigh names a differential equation that assumes this quantity is zero. A method for calculating it requires solving for theta in the equation "sum of: alpha z, over alpha minus theta, equals 1 minus q", where q is the feed condition and z is mole fraction. The Underwood equations are used to solve for the smallest possible value for this quantity, at which you'd get a pinch point and would need to draw infinite "steps". When this quantity goes to infinity, the operating lines meet the (*) 45 degree line on a McCabe-Thiele diagram and the number of stages is minimized. It equals the boilup rate over the takeoff rate, or alternatively, the ratio of flow rates of the two streams leaving the overhead condenser. For 10 points, name this ratio which measures how much liquid returns to the column during distillation.
A normalized form of this quantity is represented by X in the expression "1 + 54.4X, over 11 + 117.2X", which is Molokanov's correlation.
reflux ratio [or R; or minimum reflux ratio; or Rmin] 