Steam and Air Mixture Temperature

For a mixture of steam and air handled by an ejector, the temperature of the mixture in the ejector mixing chamber is calculated by [11]  

Cps = specific heat of steam at constant pressure corresponding lo downstream absolute pressure (0.45 approx.) is = temp of steam on downstream side of nozzle, °F Wa = Air flowrate, lbs/hr 

Cps = specific heal of air at constanL pressure (0.24 approx.) ty = ambient air temp °F 

Applied Process Design for Chemical and Petrochemical Plants 

240 psig (255 psia) 440°F total temp This is 440 — 402 sat temp = 38 superheat Temp of air from vessel 75°F Steam flow 475 lbs/hr Airflow 175 lbs/hr Ejector suction pressure 1.5 in Hg abs Then Enthalpy of steam = 1226.5 Btu/lb (from superheat vapor tables 255 psia) 

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