Energy Coasumption Analysis Of Energy-saving Circulating Fluidized Bed Boiler Under Variable Coal Condition

At present,due to the increasing demand for coal resources,most domestic circulating fluidized bed power plants cannot be used for fuel production according to the design of coal types.Most of them use mixed-burn coal types,sometimes even having a large difference from the design coal types,and this makes it difficult to guarantee the quality of combustion,which is critical to the energy consumption of the boiler.Therefore,it has important strategic significance to study the influence of coal quality characteristics on the energy consumption of circulating fluidized bed boilers and provide a basis for boiler design and coal type selection.Aiming at the single variable variation of coal composition,this paper takes a 300MW circulating fluidized bed boiler as the research object,based on the energy balance analysis method of the first law of thermodynamics,establishing the mathematical calculation model of boiler efficiency,analyzing from the aspects of the incomplete combustion loss of boiler solids,heat loss from exhaust gas,ash physical heat loss,boiler efficiency,researching the influence of changes of the single variable of coal composition-moisture and ash on boiler energy consumption,getting the quantitative relationship between the single change of water or ash and boiler loss and efficiency.Aiming at the multi-variable variation of coal composition,this paper takes a 600MW circulating fluidized bed boiler as the research object,based on actual experimental data,and establishing a mathematical model for the influence of multi-variable coal quality characteristics on boiler efficiency,studying the comprehensive effects of coal moisture,ash and low calorific value on flue gas volume,flue gas temperature,fly ash carbon content and various heat losses,getting the quantitative relationship between changes of coal quality and boiler energy consumptionIn the study of solid incomplete combustion loss and heat loss of flue gas,based on the operating data of the power plant,calculating the quantitative relationship between the carbon content of the ash and the coal quality component,and further studying the influence of the carbon content change of the fly ash on the boiler efficiency.When considering the change of exhaust temperature,analyzing the influence of different Reynolds number exponential changing on the heating surface heat transfer coefficient,and studying the influence of exhaust gas temperature change on boiler efficiency.