Question 97General Subjects - Assistant Engineer

The correct answer is B) air ejectors, eductors, or a separate vacuum pump. In a flash-type distilling plant, a vacuum is initially created using specialized equipment such as air ejectors, eductors, or a separate vacuum pump. These devices remove air and non-condensable gases from the system, allowing the feed water to "flash" into steam under low-pressure conditions. This flashing process is what drives the distillation and evaporation of the feed water, producing the distillate. The other answer choices are incorrect because they do not accurately describe the mechanism for creating the initial vacuum in a flash-type distilling plant. The flashing of the feed water (A), the condensation of the salt water feed (C), and the condensation of the distillate (D) are all results of the distillation process, not the means of creating the vacuum required for it to occur.