For midstream operators, market conditions for natural gas and natural gas liquids (NGL) dictate the approach to gas processing. For plants located further from the U.S. Gulf Coast, transportation and fractionation (T&F) fees associated with NGL can be significant, resulting in very low or negative netback prices. In this environment, some have found that the high NGL recovery does not justify the higher capital investment for highly cryogenic processes, and they are turning to lower cost alternatives. The priority for processing may be to meet sales gas specifications at a minimum cost, with liquids revenue playing a smaller role due to tight margins.
Low temperature separation (LTS) technologies have been used extensively by the gas processing industry for more than 50 years. Commonly referred to as straight refrigeration, this technology can meet gas pipeline specifications by modest NGL recovery but with significantly reduced capital investment compared to turboexpander-based technologies.
There are many configurations for straight refrigeration plants that accommodate a wide range of feed gas conditions as well as capital and operating cost requirements. Comparing the various configurations, their associated costs and performance with certain feed gas conditions enables owners to realize greater revenues from NGLs in a cost-challenged environment. Black & Veatch’s new process, LTS-PLUS™, shows particular promise as a low-cost option with increased recovery of higher value liquids.