Process for handling and utilizing system gas in a pyro-processing system

摘要

In a mixing zone of a mixing vessel, comminuted lime is fed into emission gas and carried out of the vessel with the gas to a cyclone separator. Gas from a cyclone is passed through a quench zone and excess dust from the cyclone is introduced into the gas stream for additional sulfur-dioxide removal. Off-gas from the preheat zone which contains unburned combustibles is burned in a booster heater with the heat being utilized as process heat. Excess preheat off-gas not required for preheat process is delivered to a second combustion furnace and the heat utilized for drying. From the quench zone the gas passes to two dust separators with the cleansed gas being utilized in up-draft and down-draft drying zones. Make-up lime is fed to the mixing zone from a suspension calcining furnace, reaching the mixing zone while still heated.