A heat exchange furnace includes a combustion furnace module, a passageway
module disposed around and connected removably to the combustion furnace
module, and a gas-guiding unit including upper and lower guiding modules
connected respectively to upper and lower ends of the passageway module.
During assembly, the lower guiding module is first connected removably to
the passageway module. Subsequently, the passageway module is sleeved
removably on the combustion furnace module. Finally, the upper guiding
module is connected removably to the passageway module.