炉排式垃圾焚烧炉参数敏感性分析与燃用高热值垃圾运行优化的数值模拟

针对垃圾热值提高造成的炉排式垃圾焚烧炉受热面超温问题，采用计算流体力学(CFD)方法模拟焚烧炉内垃圾焚烧过程，并将模拟结果与Morris敏感性分析方法结合，考察一次风温度、过量空气系数、干燥段风量占比和垃圾停留时间4个输入参数改变对垃圾着火位置和下炉膛最高烟气温度2个输出参数的敏感性，以评估各参数对炉内垃圾焚烧的影响，得到更为有效的运行参数调整方案。结果表明，垃圾停留时间是最敏感的控制参数，一次风温度和炉排配风比例也是较敏感的参数。在此基础上，对某1 000 t·d⁻¹焚烧炉燃用高热值垃圾运行优化开展模拟分析发现，缩短垃圾停留时间和调整炉排配风比例使着火点位置接近基准垃圾工况，使烟道前侧壁面附近温度降低93 K；进一步调整后墙二次风入射角至水平，可显著降低进料口壁面附近温度，且烟气温度、氧气和未燃气体的体积分数均满足国家排放标准。本研究结果可为炉排式垃圾焚烧炉燃用高热值垃圾的运行优化提供参考。

Sensitivity analysis on operating parameters for moving-grate incinerators and numerical simulations for improvements of burning high calorific value wastes

In order to solve the over-temperature problem on the heat exchanger surface of incinerators burning high calorific value wastes, CFD simulations were performed to analyze the combustion process in the moving grate waste incinerators. And the simulation results were combined with the Morris sensitivity analysis method to investigate the sensitivity of four input parameters of primary air temperature, excess air coefficient, proportion of primary air in the drying section and waste residence time on the two output parameters of waste ignition position and maximum flue gas temperature of the lower furnace. The influence of each parameter on the incineration of waste in the furnace, and a more effective operating parameter adjustment scheme was obtained. The results showed that of the four operating parameters, the residence time of waste over the grate was the most important controlling parameter to determine the ignition location on the grate. The primary air temperature and air distribution ratios were found as sensitive inputs. On this basis, a 1 000 t·d−1 incinerator of high calorific value wastes was numerically modelled. It was found that the combination of short residence time and a small air distribution ratio of the devitalization stage could adjust the ignition location effectively, and reduced the flue gas temperature near the front side wall by 93 K. Furthermore, by adjusting the secondary air incidence angle of the rear wall to horizontal, the wall temperature near the waste inlet decreased significantly, and the flue gas temperature, oxygen and unburned gas contents at the exit satisfied the national emission standards. The results of this study can provide a reference for the optimal operation of burning high calorific value waste in moving grate waste incinerators.