An air dryer comprising: a rotor comprising one or more walls and an interior chamber, wherein a plurality of openings are formed in the rotor and are each in fluid communication with the interior chamber, wherein the one or more walls comprise a side wall, wherein the plurality of openings are formed in the side wall, wherein at least one of the openings comprises an inlet, wherein an outlet is formed in the rotor and is in fluid communication with the interior chamber, wherein the inlet is configured to receive air containing water, wherein the rotor further comprises a desiccant cartridge, wherein an outlet is formed in the cartridge and is in fluid communication with the interior chamber, wherein the desiccant cartridge comprises a side wall with an inner surface that is sloped from the outlet to the openings; and a desiccant positioned within the interior chamber between the inlet and the outlet, wherein the desiccant comprises an outer surface positioned adjacent to the rotor and abuts the side wall of the rotor and the side wall of the desiccant cartridge, wherein the desiccant is configured to adsorb at least some of the water contained within air flowing from the inlet to the outlet, wherein the desiccant is structured so that as the rotor and desiccant are rotated at a regeneration speed at least some of the water moves to the outer surface and at least some of the water is separated from the outer surface, and wherein the sloped inner surface of the side wall of the desiccant cartridge is structured to direct water separated from the outer surface to at least one of the openings. a rotor comprising one or more walls and an interior chamber, wherein a plurality of openings are formed in the rotor and are each in fluid communication with the interior chamber, wherein the one or more walls comprise a side wall, wherein the plurality of openings are formed in the side wall, wherein at least one of the openings comprises an inlet, wherein an outlet is formed in the rotor and is in fluid communication with the interior chamber, wherein the inlet is configured to receive air containing water, wherein the rotor further comprises a desiccant cartridge, wherein an outlet is formed in the cartridge and is in fluid communication with the interior chamber, wherein the desiccant cartridge comprises a side wall with an inner surface that is sloped from the outlet to the openings; and a desiccant positioned within the interior chamber between the inlet and the outlet, wherein the desiccant comprises an outer surface positioned adjacent to the rotor and abuts the side wall of the rotor and the side wall of the desiccant cartridge, wherein the desiccant is configured to adsorb at least some of the water contained within air flowing from the inlet to the outlet, wherein the desiccant is structured so that as the rotor and desiccant are rotated at a regeneration speed at least some of the water moves to the outer surface and at least some of the water is separated from the outer surface, and wherein the sloped inner surface of the side wall of the desiccant cartridge is structured to direct water separated from the outer surface to at least one of the openings.