Heat Transfer Calculation And Analysis Of Blast Furnace Gas Waste Heat Boiler

The blast furnace gas waste heat boiler was used to recycle the heat of blast furnace gaswhich was generated in the process of ironmaking. The gas flow，heat transfer and masstransfer process in it were very complicated. So,it is necessary to research the heat transferrule of it. In this article, numerical simulation and thermodynamical calculations were usedto study it. Relative calculations on the blast furnace gas waste heat boiler wereprogrammed by Excell. The pressure of flue gas of common waste heat boiler was0.1Mpa.So the heat transfer character of flue gas under the pressure of0.3Mpa had been analyzed.What is more，numerical simulation of radiation and convection that coupled with heattransfer in the waste heat boiler was researched by CFD technology. Optimizing thestructure of it based on the analysis of flow and temperature fields. Meanwhile, the resultsof numerical simulation were compared with the results of thermodynamical calculation.Based on this comparative analysis, the suggestions for revision of the relevant empiricalparameter had been put forward. The main tasks and conclusions of this paper are listed asfollows:（1）Heat recovery project was proposed, the sectional type of waste heat boiler was triplesection such as high-temperature section, medium-temperature section and low-temperaturesection. Memberane tube wall was determined for the whole boiler.（2）According to the process of thermodynamical calculations, Semi-automotize programof thermodynamical calculations was developed by Excell.（3）The radiation heat transfer ability of flue gas under0.3Mpa pressure was analyzed,the results show that flue gas inlet temperature、radiation layer thickness and ash depositionthickness have an effect on the radiation coefficient of flue gas. While we calculate theradiation heat transfer，these factors should be considered.The heat transfer characteristic ofthe medium-temperature section and low-temperature section was analyzed，the diameter ofheat-absorbing surface was determined. The radiation heat transfer and convection heattransfer should be considered comprehensively.（4）The physical model of waste heat boiler was built，the boundary condition wasdetermined according the results of thermodynamical calculations. Flow and temperaturefields of flue gas of waste heat boiler were generated，the general distribution rules of themwere analyzed. The optimization method was established. The results of numericalsimulation were compared with the results of thermodynamical calculation. Accordingcomparative analysis, the suggestions for revision of the relevant empirical parameter had been put forward.