废气生物过滤填料层湿分迁移的数值模拟

Numerical simulations of moisture migration within packings of waste-gas biofilter

填料层湿分是生物法处理废气性能的一个主要影响因素,填料层湿分迁移的研究将为废气生物过滤系统工业放大装置的设计和运行提供依据.参考多孔介质体积平均模型和三参数模型,以流体质量和能量守恒方程为基础,建立了废气生物过滤填料层湿分迁移的数学模型,采用Galerkin有限元法,对模型进行了数值计算,并与实验数据进行了比较.结果表明,模型计算值与实测点湿度值吻合较好.气流特性与填料层湿分迁移的数值模拟显示,随着进气气速增大、相对湿度减小、进气浓度增加、温度升高,填料层的含湿量下降,且它们对湿分迁移的相对影响程度依次为:气速>温度>进气浓度>相对湿度.填料层湿分迁移速率与气速呈对数关系,与温度、进气浓度呈指数关系,与相对湿度呈负乘幂关系.

Moisture content is considered to be one of the most important parameters that affect the performance in waste-gas biofilter. The investigation of moisture migration within the packings may provide adequate data for the design and operation of a full-scale biofilter. A moisture migration model was set up based on porous media volume-averaging model and three-parameter model. By adopting the operator splitting algorithms, the Galerkin finite element method was used to deduce the discrete equations, and the calculated values of one-dimensional model for heat and mass transfer of media in biofilter for the treatment of hydrogen sulfide were in good agreement with the experimental data. The effects of air flow properties on moisture migration were also simulated. The results showed that the moisture transportation rate was in proportional to the logarithm of gas velocity, exponential of temperature and inlet concentration, power of relative humidity, and the descending order was： gas velocity 〉 temperature 〉 inlet concentration 〉 relative humidity.