A pressure exchanger for hydraulic fracking includes a rotor that is configured to rotate about an axis and includes a plurality of rotor ducts extending parallel to the axis, where each rotor duct extends between a first side and a second side of the rotor that are spaced apart from each other. The pressure exchanger further includes a first end cover that is disposed at the first side of the rotor and defines a first pair of apertures configured to communicate a first fluid including fracking particles, and a second end cover that is disposed at the second side of the rotor and defines a second pair of apertures configured to communicate a second fluid. The first end cover further defines a flush port configured to supply the second fluid into the first side of the rotor in a state in which the first pair of apertures communicate the first fluid with the first side of the rotor.