地源热泵加温沼气池内温度场分布特性分析

Distribution Characteristics of Temperature Field in a Running Biogas Digester Using Ground-source Heat Pump Heating

沼气池内温度场的分布及其变化将直接影响到整个系统的产气量和产气速率。本文在采用地源热泵加温厌氧消化池的前提下,通过在具体工程沼气池内布置三层温度探头的方法,研究和分析了中温发酵沼气池实际运行中,温度场的分布特性。结果表明,采取保温措施后发酵池外壁散热损失较小,在没有加温和进料的情况下,降温幅度在每小时0.054℃左右;进料是导致发酵池内温度下降的另一原因,在进料的十几分钟里,降温幅度可达0.5℃;在地源热泵加温过程中,池内平均升温每小时为0.27℃左右,但池内温度场分布并不均匀,呈现中下层均匀稳定,上层不均匀不稳定,中下层温度高而上层温度低的分布规律。试验结果还表明,加温盘管的位置和搅拌对池内温度场的分布也有着很大影响。该试验结果可以为研究和建立池内流场传热传质数学模型、系统设计和经济运行提供依据。

The distribution characteristics of temperature field and its changes in biogas system will directly affect the gas production rate.In this paper,ground-source heat pump was used to heat anaerobic digester to analyze the temperature field of running mesophilic digester.Three layers of temperature probing were arranged in a running biogas digester,each with 13 temperature probes.The results show that,the heat loss through fermentation tank wall is relatively small after taking insulation measures,the cooling rate is 0.054 ℃·h-1 during the time without heating and feeding.The another temperature droping is from feeding,during which the tempreture droping was up to 0.5℃ in ten minutes.The average temperature rises 0.27 ℃·h-1 during the heating.The temperature distribution in digester is not uniform.The temperature is relatively uniform and stable in the middle and lower area in the digester,while it is not uniform and stable in the upper area of digester.And the temperature was higher in the middle and lower area than the upper area in the digester.The location of heating coil and stirring also have great impact on the temperature distribution.