Sum-rates method

SR (sum-rates) method. The new liquid flow rates are taken... 

Figure 13.18. Algorithm for the SR (sum rates) method for absorbers and strippers [Birningkam and Otto, Hydrocarbon Processing 46(10), 163-170 (1967) Henley and Seader, 1981].

The "sum-rates" method of Sujata (2) also uses the temperatures and phase rates as iteration variables, but reverses the pairing. The temperatures are paired with the enthalpy balances, and the phase rates are corrected by summing the component flow rates resulting from solution of the combined component mass balance and phase equilibrium equations. This method is especially effective for wide-boiling systems, such as absorbers, but is not suitable for narrow-boiling systems. 

SR (sum rates) method, 407,409 algorithm flowsheet, 408 Standards and codes, 2, 3 Steam heaters, 45,46 Steam jet ejectors, 143, 162... 

SR (sum-rates) method. The new liquid flow rates are taken proportional to the nonnormalized sums of mol fractions, the vapor rates by subsequent material balances, and the new temperatures by enthalpy balances. A flowsketch of the calculation process is in Figure 13.17, and a brief description also is given subsequently. This method is particularly suited to separations involving substances with widely differing volatilities, as in absorbers and strippers, where the bubblepoint method breaks down. 

Separations 404 Specifications 405 The MESH Equations 405 The Wang-Henke Bubblepoint Method 408 The SR (Sum-Rates) Method 409 SC (Simultaneous Correction) Method 410... 

When all the corrections AT have approached zero, the resulting values of T are used with criteria like (15-31) or (15-32) to determine whether convergence has been achieved. If not, before beginning a new k iteration, one can adjust values of V and 7 as indicated in Fig. 15.16 and previously discussed for the BP method. Rapid convergence is generally observed for the sum-rates method. 

Application of the sum-rates method developed in Chapter 15 for the equilibrium and flow rate calculation to estimate the number of theoretical equilibrium stages, coupled with some form of HETP calculation based on experience or available correlations. 

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