Abstract:

In oil-water coalescing filtration, it is crucial to clarify the liquid distribution in the filter and pressure drop evolution for investigating the filtration mechanism and optimizing the filter structure. The liquid distribution characteristics and pressure drop evolution in filters with different pore sizes were examined. The effects of filtration velocity and loading rate on filter saturation and pressure drop were also evaluated experimentally. The results show that the liquid distribution and pressure drop changes during oil-water separation conform to jump-channel model. However, due to the presence of the liquid pool, an abrupt change of pressure drop occurs at the initial stage of the channel stage. The pore size determines the amount of liquid entering the filter, which in turn affects the liquid behavior and pressure drop variations. As the filtration velocity increases, the saturation in the large-pore filters gradually decrease, but the rate of decline gradually weakens. Meanwhile, the jump pressure drop gradually increases, while the channel pressure drop remains relatively stable. In contrast, the saturation in small-pore filter exhibits the opposite behavior. As the loading rate increases, the saturation of the large-pore filter, the jump pressure drop and the channel pressure drop increase. For the small-pore filter, as the loading rate increases, the saturation has a slight change, the jump pressure drop remains almost unchanged, but the channel pressure drop increases significantly. Finally, a prediction model for the liquid distribution in the filter was established, which can be used to quantitatively characterize the relationship between the channel saturation and the pore size, filtration velocity, and loading rate. This study provides a theoretical basis and technical support for optimizing the structure of the filter and the operating parameters, as well as reducing the maintenance costs.

Key words: coalescing filtration, oil-water separation, loading rate, pressure drop, saturation

摘要：

油水聚结过滤过程中，明晰滤材中的液体分布和压降演化对于研究过滤机理、优化滤材结构至关重要。利用油水聚结过滤材料性能实验装置，分析了不同孔径滤材中的液体分布特性和压降演化过程，深入探讨了过滤速度和液体载荷率对滤材饱和度和过程压降的影响。结果表明：油水聚结分离过程中的液体分布和压降变化符合跳跃-通道模型，但是由于液池的存在，会导致通道阶段初期的压降突变。孔径大小决定了进入滤材内部的液体数量，进而影响液体行为和压降变化。随着过滤速度的增大，大孔径滤材中的饱和度逐渐降低，但下降幅度逐渐减弱，跳跃压降逐渐增大，通道压降保持相对稳定；小孔径滤材的饱和度则恰好相反。随着载荷率的增大，大孔径滤材的饱和度上升，跳跃压降和通道压降均增加；对于小孔径滤材，载荷率的增加对饱和度影响较小，跳跃压降几乎不变，但通道压降明显增大。最后建立了滤材中的液体分布预测模型，可用于定量表征通道饱和度与孔径、过滤速度和载荷率之间的关系。本研究可为优化滤材结构和操作参数、降低维护成本提供理论依据和技术支撑。

关键词: 聚结过滤, 油水分离, 载荷率, 压降, 饱和度