What is coke less cupola?

Answer 1

a cokeless cupola is an industrial melting furnace used for remelting grey iron for casting or alloying it differs from traditional cupola furnaces in that it is cokeless.
traditional cupolas run on coke which is a refined coal product. most power plants run on coke. the traditional cupola is a vertically oriented tube filled with coke. the coke burns and is kept lit by a forced air introduced into the furnace through one or many holes in the lower third of the vertical shaft called tuyeres. the metal is introduced through the top and as the metal melts it collects in the bottom of the shaft until the collection area or well is full. the metal is then tapped out of the furnace through a hole at the furnace's base called the tap hole. it pours into a receiver, ladle, or mold.
cokeless cupolas use no coke so the inner workings of the furnace are different though they look similar from the out side. in the cokeless cupola instead of just forced air coming into the furnace at the tuyere, there are gas fired burners which provide the necessary heat to melt iron. directly above the burners is a water cooled grate that bridges the vertical shaft, creating a porous shelf that can both support the wait of fresh solid metal and allow liquid metal to drip through and collect in the well bellow. above the grate are many ceramic spheres known as the bed. the bed is super heated by the burners and reflects heat into the metal as it melts to keep it molten. iron is introduced at the top of the shaft onto the bed and when it melts and collects in the well it is tapped out as in a coke fired cupola.
operationally there are pros and cons to both methods of iron melting but cokeless cupolas are more fuel efficient, environmentally friendly, economical, and a cokeless cupola with the same bore as coke fired cupola can tap out upwards of twice as much metal because there is only iron in the well while there is approximately 60% coke in the well of conventional cupolas.