基于Fluent流场模拟的立式好氧堆肥反应器设计及试验验证

Design and experimental verification of vertical aerobic composting reactor based on Fluent flow field simulation

针对好氧堆肥反应器搅拌不均造成的堆肥过程中堆体空间腐熟度进程不一致等问题,设计了有效容积为1 m^(3)、内设3层桨式搅拌装置的立式好氧堆肥反应器,以香菇菌渣与鲜鸡粪湿重比4∶1混合为堆肥物料,利用Fluent对搅拌装置进行流场模拟分析和试验验证。结果表明,堆肥物料在流场中做上下循环运动,物料混合均匀;中层堆体温度最先达到高温期55℃以上,其次为上层堆体、下层堆体,高温期持续时间满足GB7959—2012;O_(2)含量介于13.1%~20.02%,堆体处于好氧状态;上、下层堆体生菜种子发芽指数较中层堆体先达到80%,堆肥结束时上、中、下层堆体的种子发芽指数分别为112.03%、112.03%和109.46%,完全腐熟;3层堆体的温度、O_(2)含量和种子发芽指数均无显著差异(P>0.05),与数值模拟结果一致。

The maturity of compost is inconsistent during aerobic composting in the reactor which was due to the uneven mixing.Hence,a vertical aerobic compost reactor with an effective volume of 1 m^(3) and three-layer paddle mixer was designed.With shiitake mushroom residue and fresh chicken manure at the wet weight ratio of 4∶1 as composting feedstock,the flow field simulation analysis and verification test of the mixer were carried out by Fluent.The results showed that the composting mixture was circulating up and down in the flow field,and mixed evenly.The temperature of middle layer in reactor firstly reached in the high temperature period(above 55℃),followed by the upper layer and lower layer.The duration of high temperature period of the three layers mixture met the GB 7959—2012.The O_(2) content was between 13.1%-20.02%during composting process,which indicated the mixture in reactor was in aerobic state.The germination index of lettuce seeds in the upper and lower layers of reactor reached 80%earlier than the pile in middle layer.At the end of composting,the germination index of the piles in upper,middle and lower layers were 112.03%,112.03%and 109.46%respectively,which were completely mature.There were no significant differences in temperature,O_(2) content and seed germination index among the piles in three layers(p>0.05),which was consistent with the numerical simulation results.