Question

In a distillation tower it is necessary to condense the outgoing vapors. For this, use a

water based condenser. The outgoing vapors from the tower are 1000 kmol/h of nearly pure benzene, with
latent heat of 7240 kcal/kmol. For condensation, water will be used that enters the condenser at 30
°C and leaves at 45 °C. How much cooling water is required per hour?

Answer 1

To calculate the amount of cooling water required per hour in a distillation tower, multiply the latent heat of benzene by the number of kmol of benzene. Then, divide this by the product of the specific heat capacity of water and the temperature change of the water. The amount of cooling water required per hour is 482,666.67 kg/h.

Step-by-step explanation:

To calculate the amount of cooling water required per hour, we need to determine the amount of heat that needs to be removed from the outgoing vapors. The latent heat of benzene is given as 7240 kcal/kmol. We can calculate the heat to be removed by multiplying the latent heat with the number of kmol of benzene, which is 1000 kmol/h.

Heat to be removed = 7240 kcal/kmol * 1000 kmol/h = 7,240,000 kcal/h

To convert this to cooling water required, we can use the specific heat capacity of water, which is 1 kcal/kg/°C. The temperature change of the water is given as 45°C - 30°C = 15°C.

Cooling water required per hour = Heat to be removed / (specific heat capacity of water * temperature change of water) = 7,240,000 kcal/h / (1 kcal/kg/°C * 15°C)

Therefore, the amount of cooling water required per hour is 482,666.67 kg/h.