Question 330Steam Plants - Assistant Engineer

The correct answer is C) minimum boiler load. In a steam-assisted fuel oil atomizer, the steam pressure is higher than the oil pressure at minimum boiler load. This is because at low boiler loads, the oil flow rate is reduced, and the steam pressure needs to be higher to effectively atomize the thicker, more viscous oil. The higher steam pressure helps break up the oil into a fine mist, ensuring complete combustion. The other options are incorrect because: A) design boiler load has a different steam-to-oil pressure relationship, B) high fuel viscosity would require even higher steam pressure, and D) low fuel viscosity would not necessitate higher steam pressure.