Optimization Of CFB Boilers Burning Opportunity Fuel Mixture

The circulating fluidized bed boiler(CFBB)is considered as one the most promising clean coal combustion technology for commercialization because of its characteristics of fuel flexibility and low pollutant emission.However,each boiler is designedfor certain fuels to achieve its best performance,it is difficult for the boiler to maintain the optimal efficiency by burning opportunity fuels.It is clearly that the economic and secure operation must be re-assessed.However,it is hard to make accurate assessment for the boilers burning multi-kind of fuels.Therefore,the development of a new economy and security assessment system is necessary for boilers burning non-designed fuels,which is meaningful to optimize the burning of mixing fuels.This paper developed an online assessment system to guide fuel procurement and optimize the burning of mixing fuels and applied it to two 410t/h CFB boilers manufactured by Foster Wheeler company.Mathematic models of desulfurization,ash balance,bed temperature,heat transfer were integrated in the system with further verified by the design and operation parameters.The system is able to figure out the safest operational conditions which can meet the heat and mass balance at the same time.As a result,the optimized ratio of co-firing the opportunity fuels and the corresponding parameters can be obtained.The reliability of the system model was verified by comparing the data acquired in the operational process with the design feature.It was found that the 17 main parameters from the system agreed well with the design data,expect for the bed temperature,which is lower than expected.From the comparisonit can be concluded that:(1)The system is reliable and practical.(2)Ignoring the inherent deviation,the data detected are consistent with the value of system calculation.The stability and reliability of the system have been proven by the agreement.Further analysis has been made on co-firing petroleum coke and clay dregs.In consequence,suggestions are made on the ratio of co-firing and process operation by combing the calculation result and operation condition.