Question 624Steam Plants - Assistant Engineer

The correct answer is C) be maintained in a temperature range of 160°F to a maximum of 180°F. This is the correct answer because lube oil purifiers operate most efficiently within this temperature range. Maintaining the lube oil inlet temperature within this range helps ensure optimal separation of contaminants and water from the oil, which is the primary function of the purifier. Temperatures outside this range can reduce the purifier's effectiveness. The other answer choices are incorrect because: A) the normal lube oil cooler outlet temperature may not necessarily be the ideal temperature for the purifier; B) the highest main engine bearing temperature is not the relevant factor for purifier performance; and D) the main lube oil sump temperature may not match the ideal temperature range for the purifier.