Dryer and preheater for coal before coking - employs heat from gas used to quench incandescent coke

摘要

A plant for drying and preheating coal before it goes to a coking furnace uses heat from the incandescent coke. A stream of gas is used to quench the coke and heat is transferred from this stream to a second stream of gas which is used to dry and preheat the coal. The drying gas can circulate around a closed path incorporating equipment to condense water vapour liberated during drying and including one side of a heat exchanger, the other side of which is a part of the circuit of quenching gas. Alternatively, the paths of both gases can be combined in a single circuit which includes equipment for condensing water vapour and in which the gas stream passes by a subsequent combustion chamber. The condensing equipment is an ejector condenser system. There is provision for injecting inert gas from a reserve receiver and a burner which can supply hot gas in place of or in addn. to quench gas. The plant does not incur difficulties which existing plants have because they use nitrogen or because their operation incurs risk of explosion from the formation of water gas or of corrosion through condensation. It uses less energy and costs less.