Equivalent Evaporation Quiz

Equivalent evaporation is defined as the amount of water evaporated from:

• Water at 0°C to steam at 100°C

• Water at 100°C to steam at 100°C

• Water at 25°C to superheated steam

• Water at 0°C to dry steam at working pressure

What is the latent heat of vaporization used in equivalent evaporation calculations?

• 540 kcal/kg

• 2257 kJ/kg

• 4190 kJ/kg

• 1000 kJ/kg

The formula to calculate equivalent evaporation (EE) per kg of fuel is:

What does the Factor of Evaporation represent?

• The ratio of steam to water flow

• The ratio of actual heat added to latent heat at 100°C

• The total feedwater flow

• The amount of superheat added

A boiler produces steam with 2750 kJ/kg enthalpy from feedwater at 200 kJ/kg. What is the equivalent evaporation?

• 1.2 kg/kg fuel

• 2.3 kg/kg fuel

• 1.13 kg/kg fuel

• 0.85 kg/kg fuel

Which of the following affects equivalent evaporation?

• Steam pressure only

• Feedwater temperature only

• Both steam condition and feedwater temperature

• Only fuel calorific value

In the formula , what does x represent?

• Steam pressure

• Dryness fraction

• Steam quality factor

• Steam generation rate

A boiler receives feedwater at 45°C. It produces dry saturated steam at 10 bar. What will happen to Factor of Evaporation if feedwater temperature increases?

• Increases

• Decreases

• Remains constant

• First increases then decreases

The unit of equivalent evaporation is:

• kJ/kg

• kcal/kg

• kg of steam/kg of fuel

• kg of fuel/kg of steam

If factor of evaporation = 1.15, it means:

• Steam is produced at 115°C

• Feedwater is superheated

• Heat added is 15% more than at standard condition

• Steam is wet