Superheater protection steam is taken from which system?

The correct answer is that superheater protection steam is taken from the 150 psig auxiliary steam system. This is due to the specific operational requirements for superheated steam systems, which need to operate under controlled pressure conditions to prevent any damage to the superheater elements and ensure efficient performance.

The 150 psig auxiliary steam system provides steam that is hot enough to adequately protect the superheater during operation and prevent overheating, which can occur if lower pressure steam sources are utilized. Additionally, this pressure level allows for effective operation without introducing excessive thermal stresses that might arise from higher pressure systems.

The other steam systems mentioned—such as those at 100 psig, 75 psig, and 200 psig—do not meet the specific requirements needed for superheater protection. The lower pressures may not provide enough heat to maintain the superheater in optimal condition, while the higher pressure can lead to complications or even damages if not managed correctly, making the 150 psig auxiliary steam system the ideal choice for superheater protection.