Question 98Steam Plants - Assistant Engineer

The correct answer is C) Because the tank receives high-pressure drains. The deaerating feed tank is designed to remove dissolved gases from the boiler feedwater. Since the tank receives high-pressure drains from various components in the steam system, it needs to be protected by a relief valve to prevent the tank from exceeding its design pressure. This is a safety requirement specified in the regulations governing boiler and pressure vessel design. The other options are incorrect because they do not accurately describe the purpose or function of the deaerating feed tank. The tank does not necessarily receive large amounts of water, auxiliary exhaust, or drain to the main condenser, so those would not be the primary reasons for requiring a relief valve.