The Utilization Of Flue Gas Waste Heat And Its Engineering Application

Energy-conservation, as another important energy following after the coal, naturalgas, petroleum, hydropower, and nuclear energy, plays an irreplaceable role in thecountry’s increasingly tense situation in the energy. Waste heat utilization is veryimportant part in energy-conservation. The main way of waste heat utilization is forheating, cooling, power and CCHP. The most important thing of waste heat utilization isthat the recovery heat can be used. According to different kinds of waste heat anddifferent needs, different scheme has been proposed.1. According to test and analysis of exhaust gas, the amount of a steel annealingfurnace and a annealing furnace in a work cycle which can be used is4.67×107kJ,1.13×107kJ. The bathhouses need4.54×106kJ heat. Shot workshop needs2.12×107kJheat. Heat dissipating capacity of waste heat utilization is2.12×107kJ. Both grade andamount of waste heat can satisfy the needs. By the way of waste heat utilization forheat,203,000Nm3natural gas can be saved every year. The company can save730,000Yuan every year.2. By testing and analyzing the energy consumption of the steel heat furnace,efficiency of the furnace is43.15%. Flue gas temperature at the entrance of chimney is758.6℃. The flue gas takes29.01%of total heat. Evaporative cooling takes14.77%. Airpreheated uses15.52%of total heat. The flue gas temperature has been decreased by theair form758.6℃to359.8℃. Thermal efficiency of furnace has been increased to58.6%. However, there is still too much heat wasted.3. By adjusting the order of equipment in chimney, we get higher parameters ofsteam. Four schemes of waste heat utilization for power have been proposed. Thecomprehensive evaluation of these four schemes has been carried out by using themixed analytic hierarchy process (MAHP). Scheme4with steam parameters of5.3Mpa,435℃is optimal.4. By testing and analyzing the energy consumption of a hospital, we get its hourlypower load, cooling load, heating load. According to the load statistics, CCHP system issuitable for this hospital. The energy consumption can be reduced541.5t every year.The hospital can save2,396,000Yuan every year.