Process and installation for the heat treatment of metallic objects in a fluidised-bed retort

摘要

The invention relates to a process for the heat treatment of metallic objects in a fluidised-bed retort, in which process the objects are heated in a fluidised bed and, during a treatment interval, are held at an approximately steady temperature in the fluidised-bed retort. In accordance with the temperature measured in the fluidised-bed retorte, the fluidising-gas mass flow rate or a process gas mass flow rate which is less than 75 %, preferably from 5 to 45 %, of the fluidising-gas mass flow rate is set. The invention is characterised in that the fluidised-bed retort is supplied with air and a gaseous fuel, separately and in an approximately stoichiometric ratio, these then being mixed and being combusted to form the fluidising gas, the amount of air and amount of fuel required to achieve the process gas mass flow rate being continuously supplied via one supply line each, at constant mass flow rates, and being intimately mixed above the retorte bottom, and the additional mass flow rates required for setting the fluidising-gas mass flow rate being supplied via supplementary lines which, in accordance with the temperature in the fluidised-bed retort, are shut off or opened. IMAGE