基于Levenberg-Marquardt算法的填埋场中降解产热参数反演研究

Inverse estimation of parameters for heat generation due to degradation in landfills based on the Levenberg-Marquardt algorithm

填埋场中垃圾降解产热参数是研究填埋场温度变化及热资源利用的基础。基于室内试验得到的峰值产热模型、填埋场中热传导理论以及Levenberg-Marquardt(LM)算法,提出了填埋场中降解产热参数的反演分析方法。结合填埋场实际工况,建立了填埋场热传导一维模型并得到了温度的解析解。基于某一深度的温度数据,采用LM算法反演得到了填埋场的降解产热参数,采用反演得到的降解产热参数可以计算填埋场任意深度的温度。基于产热参数可以计算得到填埋场的峰值产热速率、峰值产热时间和总产热量。以中国无锡桃花山填埋场和美国密歇根填埋场为例,分别反演得到了降解产热参数,采用反演得到的降解产热参数计算反演点之外测点的温度并与实测值进行对比,验证了反演模型的合理性和适用性。对比发现,与实际填埋场相比,室内试验的降解产热峰值更大,且峰值时间更短。与密歇根填埋场相比,无锡桃花山填埋场的前期产热速率更大,到达降解产热峰值的时间更短。

The parameters for heat generation of municipal solid waste(MSW) are the basis for studying the temperature variation and utilization of heat resource in landfills. Inverse estimation of parameters for heat generation due to degradation in landfills was proposed based on the peak heat generation model obtained from laboratory tests, heat conduction theory and the LevenbergMarquardt(LM) algorithm. One-dimensional heat conduction model was established according to practical working situation of landfills, and analytical solution was then obtained. Base on the measured temperature data of a certain depth, the parameters for heat generation were obtained by inversion using the LM algorithm. The temperature at any depth of the landfill can be calculated with the parameters. The peak heat generation rate, the time corresponding to a peak heat generation rate and total heat generation of the landfill can be calculated using the heat generation parameters. Taking the Taohuashan Landfill in Wuxi, China and the Michigan Landfill in the United States as examples, the parameters of heat generation due to degradation were obtained by inversion. The temperature of the measuring point outside the inversion point was calculated by using the degradation heat production parameters obtained from the inversion, and compared with the measured values to verify the rationality and applicability of the inversion model.It is found that the laboratory test has a larger peak heat generation and an earlier peak time than the practical landfill engineering.Compared with the Michigan Landfill, the Wuxi Taohuashan Landfill has a higher heat production rate in the early stage, and the time to reach the peak heat generation rate is shorter.