1. Condensers

2. Introduction

3. Condenser configurations

5. Types of Condensation

6. Film condensation
Physical properties
The physical properties of the condensate for use in the following equations are evaluated at the average condensate film temperature: the mean of the condensing temperature and the tube-wall temperature.

7. Condensation Outside a Single Horizontal Tube

8. Condensation Outside a Bundle of Horizontal Tubes
If the number of tubes is , then the mean heat transfer coefficient for the bundle is:

9. Condensation Inside and Outside Vertical Tubes

10. Or, we can use the following figure

11. Example
Estimate the heat transfer coefficient for steam condensing on the outside, and on the inside, of a 25mm o.d., 21mm i.d. vertical tube 3.66m long. The steam condensate rate is kg/s per tube, and condensation takes place at 3 bar. The steam will flow down the tube.

12. Collection of properties

13. Condensation outside the tube
Calculate the tube loading
Calculate the Reynolds Number of film
Using figure 12.45, estimate the heat transfer coefficient

15. Condensation inside the tube

16. Example : Design a condenser for the following duty: 45,000 kg/h of mixed light hydrocarbon vapors to be condensed. The condenser to operate at 10 bar. The vapor will enter the condenser saturated at 60 C, and the condensation will be complete at 45 C. The average molecular weight of the vapors is 52. The enthalpy of the vapor is kJ/kg and the condensate kJ/kg. Cooling water is available at 30 C, and the temperature rise is to be limited to 10 C. Plant standards require tubes of 20mm o.d., 16.8mm i.d., 4.88m (16 ft) long, of admiralty brass. The vapors are to be totally condensed and no subcooling is required.

17. Solution Only the thermal design will be done.
The physical properties of the mixture will be taken as the mean of those for n-propane (MW 44) and n-butane (MW 58), at the average temperature.