Research On The Cement Plant Low Temperature Waste Gases' Waste Heat Recovery Plans And A New Type Heat Exchanger

This issue is based on plenty of low-temperature waste gases'measured data, which is measured in the import and export of waste heat boilers of a domestic cement factory NSP cement production lines. By this data we made some research on the characteristics and heat recovery potential of the low-temperature waste gases. The results of the research show that the waste gases has some characteristics, such as low-temperature, big dust density, strong corrosion rate, large total flow, etc. In the waste-heat-recovery estimation of the low-temperature waste gases, we hypothesis that in the heat exchange equipment the AQC waste gases'temperature fell from 110℃to 60℃, and the SP waste gases'temperature fell from 160℃to 80℃. As the total flow of the cement factory's 2×2500t/d cement production lines is 316094Nm3/h, the total recovery heat is 15.8MW. We take coal combustion heat value for 29306kJ/kg, so the recovery heat is equivalent to 17000 tons coal. So, the research of waste-heat-recovery from low-temperature waste gases has very important meaning to carry out energy saving and increase cement enterprise economic benefits in the cement industry.According to the characteristics of low-temperature waste gases, we made several recovery plans in accordance with different operation conditions of heat power generation turbine. Then we made some research on the heat exchange equipment that is applied to the waste-heat-recovery of low-temperature waste gases. The survey results show that the heat exchange and dust removal are usually two separate devices, and two devices have some problems, as having too many links, occupying a large area, managing tedious etc.According to the present situation of the heat transmission equipment, this issue developed a new heat pipe heat exchanger, and made numerical simulation by the software of FLUENT. This new type heat exchanger not only has high thermal efficiency, but also has certain dedusting ability, its internal heat pipe adopting spiral finned tube form, the flue gases side and water side are circular runner. This kind of unique internal structure made the dust particles in the flue gases easy to deposit on the surface of spiral finned tube and inwall, and in the pull of gravity the dust particles falls down to the ash hopper.The research results of this issue provide references for excavating the waste heat resource and improving the efficiency of waste-heat-recovery in cement industry, and raising the functions of the heat transmission equipment.