Question 98General Subjects - Assistant Engineer

The correct answer is B) slightly less than the absolute pressure of the L.P. extraction. The absolute pressure maintained in the shell of the salt water feed heater on most flash evaporators used on steam-propelled vessels is slightly less than the absolute pressure of the L.P. (low-pressure) extraction. This is because the salt water feed heater is designed to operate at a lower pressure than the L.P. extraction steam, allowing the heat from the L.P. extraction to be effectively transferred to the feed water. The other options are incorrect because: A) the pressure would not be less than the supplied live steam pressure, C) the pressure would not be lower than the first-stage vacuum, and D) the pressure would not be higher than the second-stage vacuum.