... industrial boiler, which is based on coal, heavy oil, light oil or flammable gas as fuel, steam boiler,hot water. Working principle ... based on coal, heavy oil, light oil or flammable gas as fuel, heat conducting oil as heat carrier. Using recycled liquid pumps mandatory recycling, ... 3-6 month.steam boiler,hot water boiler Coal, Oil( Gas ) Fired Heaterthermal Boiler,steam boiler,hot water boiler