Question 87General Subjects - 1st Asst/Chief

You are correct, the answer is A) Feed water heater internal tube surfaces. The feed water heater is where the incoming feed water is heated before entering the flash chamber. This heating process can lead to the formation of soft scale deposits on the internal tube surfaces. Soft scale is more likely to form on these heated surfaces compared to the other components mentioned, such as the internal distillate cooler tubes, flash chamber vertical surfaces, or distilling condenser tubes. The other options are incorrect because they do not represent the surfaces most prone to soft scale formation in a flash type evaporator system.