Grid cooler for cement clinker - with heat exchanger to eliminate use of excess cooling air and improve thermal efficiency

摘要

Cooler is located at the outlet of a furnace employed to roast minerals. The coller consists of two grids in a closed chamber. The lower grid receives material from the upper grid, and cooling air flows upwards through both grids. The novelty is that an indirect heat exchanger is located between the two grids and is traversed by the air; and a refrigerating fluid flows through the heat exchanger to cool the air before it passes up through the upper grid. The heat exchanger pref. consists of a recuperation boiler, in which water is converted into steam by radiation from the clinker and hot air rising from the lower grid. The material pref. flows through a crusher located between the two grids. Device is esp. used in calcining cement where normally only a part of the cooling air can be used as sec. air in the furnace and a heat loss of 105-115 kcal/kg clinker results, 35-50 kcal/kg of the heat previously lost is recovered.