Reflux ratio external

The slope L/V of the operating line is termea the internal-reflux ratio. This ratio in the operating-line equation for the top section of the column [see Eq. (13-21)] is related to the external-reflux ratio R = L + i/D by... [Pg.1266]

However, the total number of equilibrium stages N, N/N,n, or the external-reflux ratio can be substituted for one of these three specifications. It should be noted that the feed location is automatically specified as the optimum one this is assumed in the Underwood equations. The assumption of saturated reflux is also inherent in the Fenske and Underwood equations. An important limitation on the Underwood equations is the assumption of constant molar overflow. As discussed by Henley and Seader (op. cit.), this assumption can lead to a prediction of the minimum reflux that is considerably lower than the actual value. No such assumption is inherent in the Fenske equation. An exact calculational technique for minimum reflux is given by Tavana and Hansen [Jnd. E/ig. Chem. Process Des. Dev., 18, 154 (1979)]. A computer program for the FUG method is given by Chang [Hydrocarbon Process., 60(8), 79 (1980)]. The method is best applied to mixtures that form ideal or nearly ideal solutions. [Pg.1274]

External reflux ratio = L/D Slope of line from xp ... [Pg.29]

R = external reflux ratio for a given separation R ,in = minimum external ratio for a given separation X = (R-R ,i )/(R+1)... [Pg.33]

This is the smallest value of external reflux ratio (L/D) which can be used to obtain a specified separation. This is... [Pg.68]

UK. = Light key component in volatile mixture L/V = Internal reflux ratio L/D = Actual external reflux ratio (L/D) ,in = Minimum external reflux ratio M = Molecular weight of compound Mg = Total mols steam required m = Number of sidestreams above feed, n N = Number of theoretical trays in distillation tower (not including reboiler) at operating finite reflux. For partial condenser system N includes condenser or number theoretical trays or transfer units for a packed tower (VOC calculations) Nb = Number of trays from tray, m, to bottom tray, but not including still or reboiler Nrain = Minimum number of theoretical trays in distillation tower (not including reboiler) at total or infinite reflux. For partial condenser system,... [Pg.105]

R = Reflux ratio = External reflux ratio for a given separation, = L/D, L = liquid rectifying column R = Actual reflux ratio, O/D Rra = Minimum reflux ratio, O/D R = Pseudo minimum reflux ratio Rmin = Minimum external reflux ratio for a given separation... [Pg.105]

The rate of withdrawal of the sidestream is 10 per cent of the column feed rate and the external reflux ratio is 2.5. Using the enthalpy composition method, determine the number of theoretical stages required, and the amounts of bottom product and distillate as percentages of the feed rate. [Pg.591]

An average external reflux ratio over a period of time At can now be defined as ... [Pg.30]

Note the Equation 3.3b shows that the reflux setting (f exp) in the cyclic operation can be considered as the average external reflux ratio. In other words, the Rexp is the ratio of the average reflux rate to the average distillate rate over a period of At. [Pg.30]

Note Reflux ratio R is defined as external Reflux ratio while the model uses internal reflux ratio... [Pg.74]

P, Emin external reflux ratio, minimum reflux ratio... [Pg.112]

It was shown in section 3.3.4 that the discrete experimental reflux ratio Rexp in the cyclic operation could be viewed as the average continuous external reflux ratio... [Pg.374]

Number of transfer units Pressure Vapor pressure Heat-transfer rate Condenser duty Reboiler duty External-reflux ratio... [Pg.3]

The overhead purity is specified as Xp = 0.95. The reflux temperature is the bubble point temperature (saturated reflux), and the external reflux ratio is set at R = 4.5. [Pg.21]

The solution is started by using Eq. (13-25) to convert the external reflux ratio of 4.5 to an internal reflux ratio of L/V = 0.818. The distillate composition Xp = 0.95 is then located on the diagonal, and the upper operating line is drawn as shown in Fig. 13-26. [Pg.21]

Reflux ratio = External reflux ratio for a given... [Pg.105]

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