Abstract: A coking oven having a coking chamber and a combustion chamber with a high temperature flue gas outlet connected to a first heat exchanger for heating cool air to cool the flue gases to an intermediate temperature, a coal dryer using the intermediate temperature flue gases for drying wet coal to a water content of a few percent by weight and preheating the coal to a temperature below the boiling point of water, a coal oiler to oil the partially dried and preheated coal, and a gas cleaner system for removing particulate matter from the low temperature flue gas coming from the coal dryer; also disclosed is an improved method of coking coal and apparatus for preheating and partially drying coal that can be added to existing coke oven structures.