2. Determine the quantity of heat required, to raise 11.100kg of water at 80.000 degrees Celsius, to saturated steam at 2250.000kPa and 71.400% dry.
ANS = kJ
Not sure where to start. I need a little help please. I do have a chart with the properties of saturated steam. Thank you.
To determine the quantity of heat required to raise water to saturated steam, you need to calculate the following steps:
Step 1: Calculate the initial temperature change
The initial temperature of water is 80.000 degrees Celsius, and the boiling point of water is 100 degrees Celsius. Therefore, you need to calculate the heat required to increase the temperature of the water from 80.000 degrees Celsius to 100 degrees Celsius. Use the specific heat capacity of water (4.186 kJ/kg·°C) for this calculation:
Heat 1 = Mass of water × Specific heat capacity of water × Temperature change
Heat 1 = 11.100 kg × 4.186 kJ/kg·°C × (100 - 80) °C
Step 2: Calculate the heat of vaporization
To change water at 100 degrees Celsius to saturated steam at 100 degrees Celsius, you need to calculate the heat of vaporization (latent heat). The heat of vaporization for water at its boiling point is 2257 kJ/kg:
Heat 2 = Mass of water × Heat of vaporization
Heat 2 = 11.100 kg × 2257 kJ/kg
Step 3: Calculate the final temperature change
Since the water needs to reach a pressure of 2250.000 kPa, you need to use the properties of saturated steam at this pressure. Refer to your chart and find the enthalpy value for saturated steam at 2250.000 kPa and 71.400% dryness. The enthalpy value represents the total heat content of the steam:
Heat 3 = Mass of water × Enthalpy change
Heat 3 = 11.100 kg × (Enthalpy value for saturated steam at 2250.000 kPa and 71.400% dryness)
Step 4: Calculate the total heat required
To find the total heat required to raise water to saturated steam, add up the calculated heats from the previous steps:
Total heat = Heat 1 + Heat 2 + Heat 3
Finally, substitute the values into the respective equations and perform the calculations. The result will be in kilojoules (kJ), as specified in the answer (ANS = kJ).