Question

A process stream of dilute aqueous solution flowing at the rate of 10 kg/s is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 kg/s. A 1-1 shell and tube heat exchanger is available. The best arrangement is

• A. counter flow with process stream on shell side
• B. counter flow with process stream on tube side
• C. parallel flow with process stream on shell side
• D. parallel flow with process stream on tube side

Hint:

Counterflow heat exchangers are more efficient than parallel flow, as they maintain a greater temperature difference throughout the exchanger.

Answer 1

The Correct Option is A

Step 1: Understanding heat exchangers.
In a heat exchanger, the effectiveness is maximized when the temperature difference between the two streams is maximized throughout the exchanger. This is achieved in countercurrent flow configurations, where the two fluids flow in opposite directions. In this case, placing the process stream on the shell side and the steam condensate on the tube side enhances heat transfer efficiency.
Step 2: Conclusion.
The best arrangement for this heat exchanger is a counterflow configuration with the process stream on the shell side. Therefore, the correct answer is (1).