A firing system for ethylene cracking furnaces

摘要

A firing system for a thermal cracking furnace is provided. The firing system includes a plurality of air inlets for introducing air into the furnace interior, the air inlets being generally arrayed along a lengthwise row on the floor of the furnace at a predetermined proximity to one of the sidewalls, and a plurality of start up fuel ports disposed intermediate the row of air inlets and the radiant coils of the furnace. The firing system also includes a plurality of normal operation fuel ports disposed intermediate the row of start up ports and the radiant coils and an assembly for selectively controlling the overall supply of fuel to the start up fuel ports and the normal fuel operation ports to effect supply of fuel solely to the start up fuel ports during a start up mode of operation of the firing system and supply of fuel solely to the normal operation fuel ports during a normal mode of operation.