METHOD FOR IGNITING A PULVERIZED-COAL ANNULAR BURNER FLAME

摘要

A method is provided herein for supplying solid, pulverized fuel to a pulverized-fuel pilot light of an annular flame, coal dust burner. The method includes, firstly, supplying the coal dust burner with a fuel stream comprising a mixture of pulverized fuel and carrier air from a pulverizing plant via a main fuel supply conduit, that stream having a cross-section with areas of pulverized fuel having different grain sizes. The second step involves selectively withdrawing a portion of the pulverized fuel and carrier air at a withdrawal site in the main fuel supply conduit which faces in the upstream direction with respect to the direction of flow of the stream so as to withdraw pulverized fuel of a grain size different from that comprising the crosssection of the entire stream. The third step involves separating the withdrawn pulverized fuel from the carrier air and returning the carrier air to the main conduit at a location downstream from the site of the withdrawal. The fourth step involves feeding the withdrawn pulverized fuel to a storage bunker for a subsequent burning by the pilot light. The fifth step involves feeding the withdrawn pulverized fuel from the storage bunker to the pilot light when the coal dust burner is extinguished wherein a flame is available for reigniting the coal dust burner when ignition is necessary. The final step involves withdrawing additional portions of pulverized fuel as described above to keep a sufficient supply of pulverized fuel of selected grain size in the storage bunker for use by the pilot light when the coal dust burner is extinguished.