A gas compression system includes a compressor operable to discharge a mixed flow of gas and lubricant, a separator tank including an opening having a first face, and a separator element including a disk portion having a second face and a third face. The separator element is positioned at least partially within the opening and is operable to separate at least a portion of the lubricant from the mixed flow of gas and lubricant. A lid is coupled to the separator tank and includes a fourth face. A one-piece seal ring is coupled to the disk and is compressed between the lid, the disk, and the separator tank to define a first airtight seal between the first face and the second face and a second airtight seal between the third face and the fourth face.