... , anthracite, weak conherent charcoal as fuel, air and steam as vaporization medicinalpreparation to produce gas as heat source. It is widely ... gas furnace, smoke exausting refractory kiln and tunnel kiln, as well as the renovation of furnaces that burn coal or oil, ... kilns, and equipment that needs heat such as metallurgy, chemical industry, allumim, fire-resistant materials, glass ...