Vacuum is generally maintained in the vapour space of an evaporator mainly to

Related MCQs

• In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator.
• A multiple effect evaporator as compared to a single effect evaporator of the same capacity has
• It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is
• For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a __________ evaporator.
• Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively).
• For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is
• A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because
• The mass of water vapour per kg of the pressure of saturated vapour at the air is known as
• The ratio of the actual vapour pressure to the pressure of saturated vapour at the prevailing dry bulb temperature is known as
• Evaporator tubes are generally