Example 3-6 NPSH Available in Vacuum System

Liquid water at 101.2°F, vapor pressure = 0.98 psia. Assume vessel liquid level is 5 feet above centerline of pump, S = + 5, worst case, Sw = 2  

The pump selected for this application (water boiling at 0.98 psia) must have a required NPSH less than 4.7 ft, preferably about 3 to 3.5 ft. This is a difficult condition. If possible the vessel should be elevated to make more head (S) available, which will raise the available NPSH. 

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Example 3-6 NPSH Available in Vacuum System, Use Figure 3-41A... 

Example 3-6 NPSH Available in Vacuum System, 191 Example 3-7 NPSH. Available in Pressure System, 191 Example 3-8 Closed System Steam Surface Condenser NPSH Requirements, 191 Example 3-9 Process Vacuum System, 192 Reductions in NPSHr, 192 Example 3-10 Corrections to NPSHr for Hot Liquid Hydrocarbons and Water. 192 Example 3-9 Process Vacuum System, 192 Example 3-10 Corrections to NPSHr for Hot Liquid Hydrocarbons and Water, 192 Example 3-11 Alternate to Example 3-10, 194 Specific Speed,... 

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