| 摘要 |
<p>In the baking of carbon anodes (for aluminum reduction cells) or the like, in so-called ring-type furnaces where green carbon bodies are deposited in pits, each of which is circumstanced successively for preheating stages, one or more baking stages, and cooling stages, while air travels in heat exchange relation through flues past a series of pits respectively undergoing such cooling, baking and preheating operations, improvement is effected by introducing water spray into the air as it flows past the pits at a cooling region. Such water, first as spray and then as vapor, increases the quantity of heat that can be absorbed by the air flow and also increases the heat transfer coefficients of the flue walls in the cooling regions, so as to provide recovery or removal of heat in greater amount or more rapidly. The vapor-containing air, advancing through the localities of baking fire in the flues and then the preheating regions, enhances the heat exchange between the gas and the flue walls and can permit higher baking temperature of the carbon bodies. A particularly important result is reduction in the overall time of the process (preheating, baking, cooling), and correspondingly in cost, e.g. as related to the production of aluminum. Suitable apparatus is a ring-type furnace with nozzles for introducing water spray into the flues that run past the carbon-containing pits. The nozzles can be connected in a manifold across the parallel lines of pits, which can be shifted as such whenever pits are brought into and removed from an operating sequence.</p> |
