Model-based analysis of micro-separators for portable direct methanol fuel-cell systems

The applicability of capillary separation to direct methanol fuel-cell systems is studied in this article from two complementary perspectives: a three-dimensional simulation with computational fluid dynamics of a gas–liquid separator, whose function is based on capillary forces rather than gravity, and a zero-dimensional model, which is integrated in the process model of a direct methanol fuel-cell system. The three-dimensional analysis indicates that an appropriate choice of construction and operation parameters allows to achieve almost perfect gas–liquid separation, and that operation is not significantly influenced by orientation. The system-wide analysis indicates that the inclusion of such a capillary separator stabilises the system, allowing the use of simpler control strategies and removing the necessity of sensors difficult to implement.

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► Model of a gas–liquid capillary separator with computational fluid dynamics.
► Study of parameters influencing separation efficiency.
► Integration in a direct methanol fuel cell system for orientation independence.
► Water content is easier to control than in reference system.