Subcooled liquid flashing

Subcooled liquid flashing/no vapour at the inlet and no non-condensable gas This scenario can be applied to hot water and covers, therefore, the ASME VIII Appendix M, Figure 11-2. 

Leung, J. C. and Grolmes, M. A., A Generalized Correlation for Flashing Choked Flow of Initially Subcooled Liquid, AIChEJ, 34 (4), 688-691, April 1988. 

Case 2 Subcooled Liquid in Orifice, Flashing in Pipe G ori= 2(n0 - T i)... 

The omega method HEM solution for orifice flow is plotted in Fig. 23-36. The solution for flashing liquids without noncondensables is to the right of = 1, and the solution for frozen flow with subcooled liquids plus noncondensables is to the left. The omega method HEM solution for horizontal pipe flow is plotted in Fig. 23-37 as the ratio ot pipe mass flux to orifice mass flux. 

FIG. 23-36 Omega method solution for orifice flow of flashing liquids and for noncondensable gas plus subcooled liquids. 

If the mixture is not flashing (a subcooled liquid with a non-condensable... 

Subcooled liquid feed Saturated liquid feed Partially flashed feed Saturated vapor feed Superheated vapor feed ... 

Subcooled-liquid feed > 1 Saturated-liquid feed = 1 Partially flashed feed 1 > > 0 Saturated-vapor feed q = 0 Superheated-vaporfeed q <0 The q value for a particular feed can be estimated from... 

So, when r s > list (low subcooling, flashing before the choke print), use the compressible solution, Eq. (26-95) with T sp = Is- Otherwise (for high subcooling, no flashing before the choke point), use the liquid orifice equation, Eq. (26-94k... 

A first estimate of whether a multicomponent feed gives a two-phase equilibrium mixture when flashed at a given temperature and pressure can be made by inspecting the K-values. If all X-values are greater than one, the exit phase is superheated vapor above the dew point (the temperature and pressure at which the first drop of condensate forms). If all X-values are less than one, the single exit phase is a subcooled liquid below the bubble point (at which the first bubble of vapor forms). 

The following stream is at 200 psia and 200°F. Determine whether it is a subcooled liquid or a superheated vapor, or whether it is partially vaporized, without making a flash calculation. 

This equation is attributed to Underwood and can be applied to subcooled liquid or superheated vapor feeds by using fictitious values of Lp and x p computed by making a flash calculation outside of the two-phase region. As with the Fenske equation, (12-27) applies to components other than the key components. Therefore, for a specified split of two key components, the distribution of nonkey components is obtained by combining (12-27) with the analogous equation for... 

---