V. Löschner, J. Meyer, A. Dittler

Separation and Purification Technology, 2025, 131093, https://doi.org/10.1016/j.seppur.2024.131093 (open access)

Some gas particle separation processes operate under low absolute pressures. Surface filter media are typically used in these applications. Little is known about the pressure drop behavior of surface filters under low pressure conditions. It is essential to obtain a more profound comprehension of filtration processes at low absolute pressures, in order to ensure the optimal sizing of the filtration system. An important factor in the layout of surface filters is the pressure drop across the filter media. In this study, the pressure drop was measured for five types of surface filter media at three filter face velocities, as a function of absolute pressure at ambient temperature in air. The absolute pressure was varied from 100 to 10⁵ Pa. It has been shown that the pressure drop across the surface filter media decreases when the absolute pressure is reduced. The measured pressure drop values of all filter media demonstrated a qualitatively analogous trend at all three velocities. Additionally, a semi-empirical model for the calculation of the pressure drop across pipes was applied. This model enables the determination of the pressure drop across surface filter media under low pressure conditions. The calculated pressure drop values demonstrate a high degree of agreement with the measured values (max. deviation of 20% down to 5000 Pa, for lower absolute pressures the deviations become higher). It is possible to calculate the pressure drop within this range using a single pressure drop measurement conducted under ambient conditions, along with the known filter face velocity, temperature, filter media- and fluid-specific parameters.