The removal of CO 2 and N 2 from natural gas: A review of conventional and emerging process technologies

Thomas Rufford, S. Smart, Guillaume Watson, Brendan Graham, John Boxall, J.C. Diniz Da Costa, Eric May

Research output: Contribution to journalArticlepeer-review

372 Citations (Scopus)

Abstract

This article provides an overview of conventional and developing gas processing technologies for CO 2 and N 2 removal from natural gas. We consider process technologies based on absorption, distillation, adsorption, membrane separation and hydrates. For each technology, we describe the fundamental separation mechanisms involved and the commonly applied process flow schemes designed to produce pipeline quality gas (typically 2% CO 2, <3% N 2) and gas to feed a cryogenic gas plant (typically 50ppmv CO 2, 1% N 2). Amine absorption technologies for CO 2 and H 2S removal (acid gas treating) are well-established in the natural gas industry. The advantages and disadvantages of the conventional amine- and physical-solvent-based processes for acid gas treating are discussed. The use of CO 2 selective membrane technologies for bulk separation of CO 2 is increasing in the natural gas industry. Novel low-temperature CO 2 removal technologies such as ExxonMobil's Controlled Freeze Zone™ process and rapid cycle pressure swing adsorption processes are also emerging as alternatives to amine scrubbers in certain applications such as for processing high CO 2 concentration gases and for developing remote gas fields. Cryogenic distillation remains the leading N 2 rejection technology for large scale (feed rates greater than 15MMscfd) natural gas and liquefied natural gas plants. However, technologies based on CH 4 selective absorption and adsorption, as well as N 2 selective pressure swing adsorption technologies, are commercially available for smaller scale gas processing facilities. The review discusses the scope for the development of better performing CO 2 selective membranes, N 2 selective solvents and N 2 selective adsorbents to both improve separation power and the durability of the materials used in novel gas processing technologies. © 2012 Elsevier B.V.
Original languageEnglish
Pages (from-to)123-154
JournalJournal of Petroleum Science and Engineering
Volume94-95
DOIs
Publication statusPublished - 2012

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