The feed enters at its bubble-point temperature; vapour from the top tray enters a total condenser; the resulting liquid (distillate and reflux) leaves at its bubble point of 32 C. The reboiler operates at a temperature of 126 C and the top tray temperature is 63 C. The column operates at a pressure of 320 kPa and pressure drops may be neglected. a) Identify the key components.
b) Calculate the minimum reflux ratio.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

Manometers are good examples of measuring instruments, nowadays they are not as common as before. a)-capacitive probe gauges b)-gravitational gauges deformation ) gauges d)-digital gauges