Introduction - Trunk Multi-functional FurnaceThe Nal Furnace is a versatile industrial boiler that can be used both as a water-cooled wall tube or superheater for heating surfaces, as well as a heat exchanger for economizers or air preheater reheaters; it can be used for direct combustion of solid fuels, and also for indirect combustion utilizing waste heat from flue gases; it is suitable for boiling water and heating purposes alike.