Abstract: An arrangement for utilizing the heat contained in the exhaust gas from a coal-fired boiler for preheating feed water for the boiler and for preheating primary air. The arrangement includes a rotating heat transfer unit and lines for conducting exhaust gas and preheated combustion air to the heat transfer unit. A heat shifting unit is connected in parallel to the heat transfer unit. A line conducts primary air to the heat shifting unit and another line conducts cooled exhaust gas from the heat transfer unit to the heat shifting unit. The exhaust gas line and the cooled exhaust gas line connecting the heat transfer unit and the heat shifting unit are connected through a bypass which bridges the heat transfer unit. The bypass includes a heat exchanger and/or steam generator, wherein the boiler feed water flows through the heat exchanger and/or steam generator.

Abstract: A method and an apparatus for the denitrification and desulfurization of hot waste gases, particularly from furnaces. A crude gas flow is initially conducted through a denitrification plant and through the endothermic part of a heat-utilizing plant. Subsequently, the flow is conducted into a desulfurization plant. The purified gas flow discharged from the desulfurization plant is conducted through the exothermic part of the heat-utilizing plant and is subsequently transferred to ambient. By means of a cooling trap, a portion of the heat contained in the crude gas flow before the contact with the heat-utilizing plant is removed while precipitating sulfuric acid in the form of vapor, and this heat is then added to the purified gas flow before the contact thereof with the heat-utilizing plant.

Abstract: In order to obtain the requisite chimney temperature of cleaned gas discharged from a desulfurizing installation, and in order to avoid problems resulting at temperatures below the dew point of sulfuric acid in heat exchangers made of steel, the invention provides the following measures: the heat exchange between the crude gas stream and the cleaned gas stream is made in a first stage including conventional heat exchangers made of steel. An additional stage of heat exchangers between the crude and cleaned gas streams is constructed of corrosion-resistant and adhesion inhibiting plastic material and operating in a lower temperature range. Transfer conduits of corrosion-resistant material connect the lower temperature heat exchangers to forcibly transfer a heat carrying fluid.