低浓度煤层气吸附干燥装置布气系统数值模拟研究

Numerical simulation of gas distribution system in low concentration coalbed methane adsorption drying device

以吸附干燥装置气体均匀分布为出发点,基于流体力学相关理论建立数学模型,对低浓度煤层气吸附干燥装置布气系统进行数值模拟研究,提出了吸附塔内布气系统的优化方法。通过计算发现,对于实际应用中的圆柱干燥塔,由于进气管与塔体连接处结构设计欠佳,轴向气流分配不均非常严重,气流速度的绝对不均匀系数为1.028;在吸附塔内安装孔板型布气系统,挡板上小孔整体排列,孔径均为3.0 mm,气流速度的绝对不均匀系数由1.028下降到0.321,均匀性得到改善;将布气系统挡板中心的孔径减小到1.5 mm,将靠近壁面的孔径增大到4.5 mm,再将小孔按正三角形排列,气流速度的绝对不均匀系数进一步降为0.101,气流分布更加均匀。

Based on the uniform distribution of gas in the adsorption drying unit,a mathematical model was established by using the relevant theory of fluid mechanics.The gas distribution system of low concentration coalbed methane adsorption drying unit was studied by numerical simulation,and the optimization method of gas distribution system in adsorption tower was put forward.Through calculation,it is found that for the cylindrical drying tower in practical application,due to the poor structure design of the connection between the intake pipe and the tower body,the uneven distribution of axial airflow is very serious,and the absolute non-uniformity coefficient of gas flow velocity is 1.028;if the orifice plate type gas distribution system is installed in the adsorption tower,and the holes on the baffle plate are arranged as a whole,with the same aperture of 3.0 mm,the absolute non-uniformity coefficient of gas flow velocity decreases from 1.028 to 0.321,and the uniformity is improved;the aperture of the baffle center of the air distribution system is reduced to 1.5 mm,and the aperture near the wall surface is increased to 4.5 mm,when the holes are arranged in an equilateral triangle,the absolute non-uniformity coefficient of gas flow velocity is further reduced to 0.101,and the flow is more evenly distributed.