US Patent 11679368 Process-intensified flow reactor

A flow reactor has a module having a process fluid passage with an interior surface, a portion of the passage including a cross section along the portion having a cross-sectional shape, and a cross-sectional area with multiple minima along the passage. The cross-sectional shape varies continually along the portion and the interior surface of the portion includes either no pairs of opposing flat parallel sides or only pairs of opposing flat parallel sides which extend for a length of no more than 4 times a distance between said opposing flat parallel sides along the portion and the portion contains a plurality of obstacles distributed along the portion.