| Oxygen Enriched Combustion technology is generally called as OEC, which refers to mixing and burning fuel with oxygen-enriched air whose oxygen concentration is above 21%, higher than that of ordinary air. It is a new type of energy-saving technology in the modern combustion field with the advantage of improving fuel efficiency, strengthening furnace radiation heat transfer, reducing the loss of exhaust heat and emissions of pollutants.Steel heating furnace and oxygen enriched combustion technology is briefly overviewed, and the current research progress and application status of the oxygen enriched combustion technology in steel heating furnace at home and abroad are analyzed. The energy efficiency analysis and numerical simulation of the oxygen enriched combustion technology in some steel heating furnaces have been conducted by employing Process Heating Assessment and Survey Tool(PHAST) software and Fluent software respectively. The objective of the present paper is to mainly investigate the influence on the heat efficiency of steel heating furnace when the oxygen concentration in the combustion air is increased.Firstly, the energy efficiency analysis of Canada Gerdau steel heating furnace was carried out with the PHAST software, and the heat loss, energy consumption and thermal efficiency within the heating furnace were simulated under different oxygen concentration(21%, 27% and 100%). And then the CO2 emission reduction, the OEC cost and economical efficiency were analyzed when the heating furnace was retrofitted to oxygen enriched combustion instead of conventional air combustion.The result shows that the furnace energy consumption and total heat loss decreases when using OEC, the energy-saving rate and thermal efficiency increases with oxygen concentration in combustion air. The emission intensity of CO2 reduces and thus the steel production and economical efficiency increases by using the OEC.Secondly, numerical simulation of an experimental regenerative slab reheat furnace in Nippon Kokan with the oxygen enriched combustion was conducted with Fluent software. The influence of the oxygen concentration increase in combustion air on the velocity distribution, temperature distribution and flue gas species distribution has been obtained, and the comparison with experimental data of the furnace is also deployed. The result shows that, the inlet velocity of oxygen-enriched air significantly decreases under the same cross-sectional area of burner air vent when the oxygen enriched combustion is adopted. The maximum temperature and average temperatureincreases with the increase of the oxygen concentration in combustion air. The mass fraction of nitrogen reduces while the mass fractions of the CO2 and H2 O increases when using the oxygen enriched combustion. The relative error between the numerical results and experiment data is less than 5%, which further verifies the accuracy and feasibility of the numerical simulation method. |
PDF Full Text Request