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US 4,788,917 AGranted
Shaft furnace bypass system
AssigneeFuller Company
InventorDavid J. Hogue
Life of this patent
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AssigneeFuller Company
InventorDavid J. Hogue
Estimating the term…
A method and apparatus for removing undesired compounds such as alkali compounds from a shaft furnace such as a blast furnace. The process and apparatus includes providing a plurality of intermediate exhaust conduits or manifolds within the shaft furnace for withdrawing some of the furnace gases which may be rich in alkali or other undesirable compounds from the furnace while allowing the balance of the gases of combustion to rise through the furnace. These conduits are positioned so that the temperature below the conduits is higher than the temperature at which the alkali compounds will volatilize and the temperature above the conduits is lower than the temperature at which the alkali compounds will condense so that the undesirable alkali compounds are in a vapor state when they are withdrawn from the furnace through the intermediate exhaust conduits. These alkali rich gases are then exposed to a cool surface such as an abrasive material being pneumatically conveyed through the intermediate conduits so that the alkali compounds condense on the cool surface. An apparatus and method including a fluidized bed system is also disclosed for cleaning the abrasive material so that it can be recycled to the conduits within the furnace.
A method for removing undesirable condensible materials such as alkali compounds which may be contained in the material charge or the fuel burned in a shaft furnace wherein fresh material charge is supplied near the top of the furnace and product is discharged near the bottom of the furnace and hot gases rise upwardly through the furnace toward the top in counter-current contact with the material charge, the method comprising the steps of separating a portion of the rising furnace gas containing volatilized undesirable material from the remaining hot gas at a location intermediate the top and bottom of the furnace where the temperature within the furnace is higher than the temperature at which the undesirable material condenses on the fresh material charge, condensing the volatilized undesirable material contained in the separated portion of the rising hot gases and allowing the remaining furnaces gases to continue to rise upwardly through the furnace.
In a shaft furnace for thermal processing a charge of material wherein raw material to be processed is supplied to the furnace near the top thereof and product is discharged from the bottom of the furnace and hot gas produced by combustion of fuel within the furnace rises through the shaft furnace countercurrent to the downward flow of material, apparatus for removing condensible undesirable compounds which may be contained within the charge of material comprising means for separating a portion of the hot gases rising in the furnace which contain volatilized undesirable compounds including at least one conduit means for withdrawing gas from the shaft furnace at a location where the temperature in the furnace is higher than the temperature at which the undesirable compounds will condense, and means for condensing the undesirable compounds which are contained in separated portions of the hot gases.
Dependencies are inferred from the claim text.