Question 380Steam Plants - Assistant Engineer

A) source of ignition for the explosive mixture is the correct answer. For an explosion to occur in a boiler furnace, three elements must be present: an accumulation of unburned fuel, sufficient air to form an explosive mixture, and a source of ignition to ignite the explosive mixture. Without a source of ignition, such as a spark or flame, the explosive mixture cannot be ignited, and an explosion will not occur. The other options are incorrect because they do not directly address the necessary components for an explosion. A large space is not required for an explosion, and high steam demand or a grounded burner ignition electrode are not directly related to the conditions needed for an explosive event in the boiler furnace.