Question 90General Subjects - Assistant Engineer

The correct answer is B) an air leak through a vacuum gage line in the first stage. If the distilling plant's first stage absolute pressure is higher than normal while the second stage absolute pressure remains satisfactory, the probable fault is due to an air leak through the vacuum gage line in the first stage. This is because an air leak in the first stage would increase the absolute pressure in that stage, while the second stage would remain unaffected, as the air leak would be isolated to the first stage. The other options are incorrect because priming in the second stage (A) would affect both stages, a loss of the distillate loop seal between the stages (C) would affect both stages, and a failure of the brine pump (D) would not specifically cause the first stage pressure to be higher than normal.