Abstract:

With the gas flow rates of 5-25 m³·h^-1 and liquid flow rates of 0.2-0.6 m³·h^-1, the fluid mechanics performance of a Venturi gas-liquid distributor were investigated in a trickle bed reactor with an internal diameter of 28 cm. The Sauter mean particle size of the outlet droplets was measured with a laser particle size analyzer. The distribution uniformity was determined by using a liquid collection tray and special model tests were designed to test resistance to tray unlevelness. The results show that the Venturi structure enhances the gas-liquid mixing. Compared with the bubble cap type distributor, this distributor has a better droplet crushing performance. The increase of the gas velocity causes the outlet liquid changing from the umbrella flow to the jet flow, but it can still distribute evenly in the area where the diameter is approximately 10 times the diameter of gas-liquid outlet. When the gas and liquid loads are 10-20 m³·h^-1 and 0.4-0.6 m³·h^-1, respectively, the liquid level is between liquid inlets and gas inlets, the distributor has excellent performance of resistance to tray unlevelness. The computational fluid dynamics software is used to simulate the gas-liquid flow process inside the distributor, and the vector diagram of phase content and velocity is obtained, which is beneficial to the analysis and improvement of the distributor.

Key words: gas-liquid distributor, cold model experiment, gas-liquid mixing, distribution uniformity, computational fluid dynamics

摘要：

以一种文丘里型气液分布器为对象，在直径为28 cm的冷模装置中考察了其流体力学性能。气、液流量分别在5~25 m³·h^-1、0.2~0.6 m³·h^-1范围内，使用激光粒度仪测量了液滴Sauter平均粒径（D₃₂），并测定了其分布均匀性和抗塔板倾斜性能。结果表明：文丘里结构加强了气液混合，与泡罩型分布器相比，此分布器具有更好的液滴破碎性能；气速增大会使出口液体从伞状流变为喷射流，但仍能在直径约为出口直径10倍的区域内均匀分布；在气、液相负荷分别为10~20 m³·h^-1、0.4~0.6 m³·h^-1时，液位在进液口和进气口之间，此时分布器具有优异的抗塔板倾斜性能。采用计算流体力学软件模拟了分布器内部气液流动过程，得到了相含率和速度矢量图，所得结果有利于分布器的分析与改进。

关键词: 气液分布器, 冷模实验, 气液混合, 分布均匀性, 计算流体力学