Flash graphical methods

Morris et al.[6] have proposed a graphical method for estimating vent flow rate for high viscosity flashing fluids The method is semi-empirical and is fitted to experimental data for fluids with viscosities up to 750 cP. 

A graphical method for obtaining the composition y and x of the exit equilibrium streams as a function of if/ consists of finding the intersection of the operating line with the equilibrium line. Assume, for instance, that a feed of 60 mole% n-hexane in n-octane enters a flash drum at 1 atm. If = 0.5, then -( — )lif/ = -. A line of slope -1 passing through (z = 0.6) intersects the... 

It is impractical to analyze the multistage flash drum process with the graphical method we devised for a single flash drum. The problem is the recycle streams -it is awkward to determine the net composition of the flow into a particular drum. For example, how would you account for the liquid effluent from the second unit in Figure 4.62 being recycled to the first unit Yet multistage distillation should be no more difficult to analyze than multistage absorption. What is the problem ... 

Equilibrium Flash Vaporization and Partial Condensation Graphical Multistage Calculations by the McCabe-Thiele Method Batch Distillation... 

We will use this method to develop two more graphical tools - one for the analysis of flash drums and another for multistage countercurrent distillation columns. There are many others - one cannot possibly learn them all. Again the key is to know how to create graphical design tools. 

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