A system for filtering particles within a multiphase fluid that comprises a particulate phase is disclosed. The system comprises a first plurality of substantially parallel, substantially planar thin slabs separated by a predetermined distance to retain particles having a maximum cross-sectional dimension greater than the predetermined distance, and provides at least one flow path for at least part of the multiphase fluid. In one application, the system is used in connection with an electrochemical power source and components thereof, wherein the multiphase fluid comprises flowable fuel.