Question 70Steam Plants - 1st Asst/Chief

The correct answer is D) internal desuperheater flange. The reasoning is that if boiler water chemicals are decreasing in one boiler and increasing in the other boiler, while both are steaming at normal rates, it indicates a leak in the system, likely at the internal desuperheater flange. The desuperheater is a component that mixes steam and water to control the temperature of the steam, and a leak at the flange connecting this component would allow steam and water to mix, affecting the chemical balance in the two boilers. The other options are incorrect because a leak in the superheater tubes, economizer tubes, or feed water crossover line would not necessarily result in the observed chemical imbalance between the two boilers if they are both operating normally.