★Specialized Examination for Chemical Engineering ★ — One question per day (2015-11-26) — Points are awarded for participation

Thread Content

This post was last edited by zshiwei2008 on 2015-11-27 08:18. Points system for the daily question: Participation – 1~3 points; Correct answer – 5 points; In-depth analysis – 5~10 points. The answer is provided the next day. Due to limited capabilities, I am unable to provide more in-depth explanations for each question; therefore, on the second day, in addition to offering reference options, I will also remove the restriction on reading replies. I hope that all candidates can learn from one another and improve together! Daily Question (2015-11-26): 1. A chemical plant has a heat exchanger that uses saturated steam to heat air. After operating for some time, it was found that the temperature of the air at the outlet did not reach the original level. What is the reason for this? A. Increased air humidity B. The heat exchanger needs to be cleaned C. Reduced steam flow D. Any of the above three reasons could be applicable. 2. Saturated water vapor condenses outside a circular tube with an outer diameter of 20 mm and a length of 2 m. If all other conditions remain the same, and this circular tube is changed from a vertical to a horizontal position, the change in the external condensation heat transfer coefficient of the tube is ( ). A. It is approximately twice as much when placed horizontally compared to vertically. B. It is slightly less when placed horizontally compared to vertically. C. It is about half as much when placed horizontally compared to vertically. D. It is the same whether placed horizontally or vertically. Answers: 1. D 2. A. For detailed explanations, see the reply under the sofa section