A nonlinear control strategy based on Interconnection Damping Assignment Passivity Based Control (IDA-PBC) is proposed for a process with bidirectional flow. The bidirectional flow condition introduces singularities in the control action under certain operation conditions. A solution to this problem is proposed such that operation through the singular points is possible and the stability conditions around the desired operation point are exactly preserved. In addition, a passivity based integral action is included in order to take into account the effects of model uncertainties and unknown step like perturbations. A description of the process and the controller design methodology is presented along with some numerical simulations illustrating the closed-loop behavior of the proposed controller.