循环流化床锅炉新型移动床冷渣器换热特性研究

Study on Heat Transfer Characteristics of a New Novel of Bed Slag Cooler in Circulating Fluidized Bed Boiler

对循环流化床锅炉底渣余热回收与利用进行研究,发现存在回收的余热品质不高的问题,提出了错流式移动床技术的CFB锅炉底渣余热回收新方案。依据工业试验数据,利用数值模拟方法,研究了错流式移动床级数对气固流动与换热特性的影响。工业试验结果表明,采用双回程布置的错流式移动床冷渣器,在进渣温度为860℃时,冷渣器的出口风温最高可以达到779℃,显著提高了余热品质。模拟计算结果表明,三回程错流式移动床冷渣器的出口风温最高可达839℃,出渣温度最低可降至约102℃,且出口风温、流动阻力和出渣温度存在耦合关系。

A novel process of effective waste heat recovery from high-temperature circulating fluidized bed(CFB)boiler bottom ash using the cross-flow moving bed technology was presented in response to the issues with heat recovery from CFB boiler bottom ash.The impact of the cross-flow moving bed’s stage on the characteristics of the flow of gas and solids and heat transfer was investigated using data from industrial test experiments and the numerical simulation method.According to the results of an industrial test,when bottom ash was introduced at a temperature of 860℃,the bottom ash cooler’s outlet air temperature may be raised to 779℃,producing high-quality waste heat.The simulation results showed that the three-stage cross-flow moving bed bottom ash cooler can reach a maximum output air temperature of 839℃and a minimum outlet ash temperature of approximately 102℃.Correlations exist among flow resistance,output ash temperature,and outlet air temperature.