Question 219Steam Plants - Assistant Engineer

The correct answer is B) The diffuser is burned out. When the diffuser of a mechanically atomized burner is burned out, it can no longer effectively atomize the fuel. This results in the fuel not being properly dispersed and mixed with air, causing the flame to be blown away from the burner tip when attempting to light off. The other options are incorrect because: A) Insufficient excess air would cause the flame to be too rich, not blow away. C) Fuel oil viscosity that is too low would result in over-atomization, not blowing the flame away. D) Improper adjustment of the secondary air cone would affect air supply, but not necessarily cause the flame to blow away.