Show UNBURNED combustible FROM COKES one of the desirable properties of a fuel for use in in I 1 I 1 domestic i furnaces is that it should be possible to allow the tuel fuel bed to burn until only a small quantity of fuel is left and yet be able to add fresh fuel without the fire going out or without the use of kindling cokes give more trouble double because of failure to start the fresh charge than do coals the quantity of coke left in a furnace when the he fire anre is allowed to burn itself out is one measure of this ability a y to start a fresh charge measurements of this un burnt urtle fuel el have been made in a series of tests being coned ducted at the pittsburgh experiment station of the united states bureau of mines the quantity of fuel increases creases with the size of the coke pieces as fired this increase was found to be approximately proportional to the mean screen size size of the coke up to 14 mean screen size above this size the rate of increase tends to be less the quantity of fuel decreases slowly as the rate of burning 1 I increases this decrease being an more rapid for rates of burning Z below two pounds per square foot per hour the quantity of fuel varies with different cokes it does not appear to be related to any one other quality for high temperature cokes but light weight cokes gave gave lower residue the combustible residue from the low temperature cokes tested was lower than for the high teni tem pera ture coke |