Removing carbon di:oxide from protective furnace atmos. - derived from part of fume gases

摘要

In a continuous metal-treating furnace with a protective atmos. formed by partial combustion of gas, wherein a heating chamber for the moving stock is followed by a cooling chamber, the protective furnace atmos. is formed by reducing the CO2 content of a recycled portion of fume gas. This portion is washed in a tower by cleansing fluid which then passes through a circuit for expelling the absorbed CO2. This circuit includes a heat exchanger which is located in the cooling chamber and hence utilises the heat from the travelling stock which would otherwise be wasted. Many metallurgical heat treatments require a low CO2 content in the furnace atmos., e.g. to prevent take-up of carbon. This generally involves separate units and extra energy consumption, which the present plant obviates.