What are the differences between charcoal furnace and charcoal kiln when using machine made charcoal equipment?

Earth Kiln usually needs comparative long time, about 7-8 days during carbonization process. The exhaust gas is bad for human health and pollutes the environment. The complicated operation makes the production process of earth kiln inconvenient. If temperature is not properly controlled, the charcoal is easy to be burn into ashes. 

Comparatively the production cycle of charcoal furnace is shorter, about 1 or 2 days before discharging. And the carbonization chamber is closed which could decrease the ashes.  There is purification plant at the bottom of the charcoal furnace which saves manpower. What you have to do is stand by the side of the furnace to examine the temperature and pick up information.