The environmental reliability of gas-fired boiler units by app lying modern heat-recovery technologies

Abstract

Purpose. Improving the environmental safety of chimneys of heating boiler plants with exhaust-gas heat-recovery systems based on the use of the air method to prevent condensation in the exhaust ducts in combination with the method for drying the gases by heating them. Methodology. In conducting computational studies, the well-known methods for thermal calculation of boiler plants and chimneys were used, as well as the results of our own experimental studies regarding heat transfer and hydrodynamics during deep cooling of the exhaust-gases of boiler plants. The studies were carried out using single thermal methods in the heat-recovery schemes of boiler plants to prevent condensation in the exhaust ducts (drying flue gases and the air method) and a complex of these methods. At the same time, various options for heat-recovery systems and chimneys were considered in the presence of air heaters in boiler houses and in their absence. Findings. The thermal and humidity characteristics of the exhaust gases at the mouth of the chimneys were studied at used dry and heated air to reduce the humidity of these gases with a wide temperature change. Under the conditions considered, the main parameters of the chimney anti-corrosion protection systems were determined to prevent condensation in them under normative operating conditions of these chimneys. Based on the values of the obtained parameters, a comparative analysis of the effectiveness of the considered methods for protecting gas exhaust paths for various heat-recovery plants was performed. It is shown that for heating boilers, the use of the air method is most effective in complex-heat recovery systems, characterized by the use of recovered heat to heat the return heat-network water and combustion air Originality. For the first time, the application of the air method to prevent condensation in the gas exhaust paths of boiler plants with complex heat-recovery systems has been investigated. Practical value. The use of the proposed complex of thermal methods will significantly increase the reliability of the chimneys of heating boiler units in municipal heat-power engineering.