Question 357Motor Plants - Assistant Engineer

The correct answer is C) From having passed through "23". The latent heat required to create vapor from the feedwater in the illustrated distiller is obtained as the feedwater passes through device "23", which is likely a preheater or heat exchanger. As the feedwater passes through this component, it absorbs heat, which provides the necessary latent heat to transform the liquid water into vapor. This is a common process in distillation systems, where the feedwater is preheated before entering the main distillation chamber to improve efficiency and reduce energy consumption. The other options are incorrect because: A) The contact period with heat exchanger "3" does not directly generate the latent heat for vaporization; B) Device "20" is likely not the sole source of the latent heat; and D) Device "24" is likely the distillation chamber, where the vaporization occurs, rather than the source of the latent heat.