... is used extensively in the various field, such as the steel, machinery, building materials, petrochemical industry, colored metal etc, ... as different kinds of heating furnaces, hot-blast furnace, heat-treatment furnace, cracked stove, roaster, melting furnace, hot stove, oil gas boiler, etc. ... more than 15%, decreased more than 40% that billet steel is oxidized and burnt, NOx tap smaller than 100ppm, ...