| Iron and steel group will produce by-product gas,which is a very good secondary energy during production. The by-product gas calorific value is lower and the flow fluctuation characteristics,leading to the furnace temperature dropped and the flame propagation speed decreases.The oxygen enriched combustion technology can effectively improve the combustion characteristics of gas-fired boiler.In recent years, the study of oxygen enriched combustion technology mainly concentrated in the coal fired boiler, and less research on the gas boiler.taking some iron and Steel Group as the object of study,Study on combustion characteristics of oxygen enriched gas using theoretical analysis, numerical method and experimental method of boiler.First of all,using the furnace heat exchanger model demonstrates the feasibility of improving the low load stable combustion.Detailed analysis has been made about the effects of oxygen-enriched combustion on the flu gas temperature、gas radiation characteristics\flame propagation speed、ignition energy、residence time of flue gas in the furnace and so on. The results showed that:the oxygen-enriched combustion technology can improve the overall performance of the boiler very well.Secondly,the combustion characteristics of gas boiler are studied with the method of numerical simulation,by the Oxygen-enriched combustion technology. The results showed thatwith the increase of oxygen content,in the burner section the average velocity changed little,the temperature of furnace of flue is found to have more significant improvement;Compared with conventional combustion,when the fuel ratio is 100%,the amount of oxygen enrichment to 30%,the temperature of the burner cross-section increased by nearly 85℃,the high temperature reaches 1745K,so that the temperature near the outlet of the burner area the burner may be damaged.When fuel ratio is 80%, and the amount of oxygen-enriched up to 30%,the gas burner section temperature is higher than rated.conditions.Thereby,the Oxygen-enriched combustion technology improved the stability of the gas-fired boiler at low load operation.With the increase of the oxygen content in combustion furnace wall heat load and heat load are sectional burner in creases,when the fuel ratio is 100%, the ratio of 30% enriched, the radiative heat flux density exceeds 9.5× 105W/m2;wall more concentrated high load, high load region becomes gradually smaller.Finally,The combustion characteristics of by-product gas are studied in the Oxygen-enriched condition.Compared with conventional combustion,with the increase of oxygen content,theoretical combustion temperature increased,the boiler flue gas heat loss and chemical incomplete combustion loss decreased in different degree,boiler efficiency improved.When the oxygen content input reaches25.07%,the theoretical combustion temperature of fuel is increased by 134℃,the thermal efficiency of the boiler is improved by 2.02%.Economic benefit from the fuel savings generated reaches 1,613,500 yuan,reducing CO2 emissions by 17.42 × 106m3/a. |
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