  The implementation of boundary conditions is among the most challenging parts
of modeling fluid flow through channels and complex media. Here, we show that
the existing methods to deal with liquid-wall interactions using multicomponent
Lattice Boltzmann are accurate when the wall is aligned with the main axes of
the lattice but fail otherwise. To solve this problem, we extend a strategy
previously developed for multiphase models. As an example, we study the
coalescence of two droplets on a curved surface in two dimensions. The strategy
proposed here is of special relevance for binary flows in complex geometries.
