Question 70, Morning Session, Day 1 of the 2014 Registered Chemical Engineer Professional Examination
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70. In a gas turbine equipped with a shell-and-tube cooler, the cooling gas is cooled from 390°C to 100°C. Regarding the cooling schemes and the choice of cooling medium, which of the following options are not suitable? (A) Cooling with circulating cooling water (B) Cooling with fresh primary water (C) Cooling in a closed loop using heat transfer oil, followed by cooling the heat transfer oil with circulating water (D) Cooling in a closed loop using pure water at a temperature difference of 30°C, followed by cooling the pure water with circulating water. Personally, I think it’s ABD; I’m not sure about the details. Please give me some advice.
Please, someone knowledgeable can help answer this. I don’t understand what the exam is about
It should be ABD. The temperature difference is too large; it’s not suitable for cooling
In the US, the temperature difference is too large. Moreover, the question specifies that the temperature is to be reduced from 390°C to 100°C, with 100°C being the lowest temperature. If water is used for cooling, vaporization of the cooling water will occur. Option C involves first stopping the heating of the heat transfer oil and then using cooling water for cooling, which prevents the aforementioned problem from occurring
I think this question is very simple. The temperature difference is too large; circulating water simply cannot be used with such a high temperature difference, as it will vaporize immediately. It’s common sense
No circulating water is used because the temperature is high and the temperature difference is large, which makes it easy for scaling to form in the circulating water. Vaporization? As long as there is enough water, it can be set to whatever temperature is desired; it won’t vaporize