Question 67Steam Plants - Assistant Engineer

The correct answer is A) drum-type boiler. A natural circulation water-tube boiler, with one or more water drums, is classified as a drum-type boiler. This is because the water drums in a natural circulation boiler act as the primary water storage and steam separation vessels, which is the defining characteristic of a drum-type boiler design. The other options are incorrect because: B) is a specific type of natural circulation boiler, C) refers to a header-type boiler design, and D) describes a boiler with controlled water circulation, which is different from natural circulation.