New Gas-Separation Technology Reduces Cost, Weight, and Footprint

Abstract

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper OTC 29001, “Novel Adsorption-Based Gas-Treating Technology Platform for Upstream Gas Separations,” by William Barnes, Chien-Chiang Chen, Tracy Fowler, SPE, Patrick McMahon, SPE, Ananda Krishna Nagavarapu, SPE, and Donald Shatto, ExxonMobil, prepared for the 2018 Offshore Technology Conference, Houston, 30 April–3 May. The paper has not been peer reviewed. Copyright 2018 Offshore Technology Conference. Reproduced by permission. Hydrocarbon processing and treating systems often require large and elaborate surface facilities. When operating in challenging locations, such as deep water or the Arctic, these systems can be expensive. This paper discusses a new adsorption-based gas-separation technology platform to address these challenges. The technology uses rapid pressure- and temperature-swing cycles to reduce equipment size and weight and the overall gas-treating footprint by approximately 50% compared with conventional technologies. The savings are particularly beneficial in locations where space is limited. Furthermore, the technology is well suited for skid-based deployment, which provides execution efficiencies. While the technology platform is broadly applicable for a variety of upstream gas separations, development is currently focused on deep dehydration and carbon dioxide (CO2) removal before cryogenic gas processes, such as liquefied natural gas (LNG) or natural gas liquid (NGL) recovery. Extensive fundamental research, including laboratory and pilot testing, has been completed to demonstrate technical feasibility. Construction of a field research and demonstration facility is under way as of this writing to demonstrate scaled-up operation over a wide range of operating conditions. Introduction In the interest of making oil and gas developments economically viable, oil and gas companies are focused on reducing the cost of treating and processing facilities. Execution and operational efficiency benefits are added incentives to reduce the size, weight, complexity, and footprint of these facilities, particularly for offshore installation. Pursuing these incentives, the operator is developing a new adsorption-based gas separation technology platform targeting a broad range of upstream separation needs. Adsorption-based separation processes are used in gas conditioning for applications such as dehydration, CO2 removal, and helium recovery. These are often considered batch processes, in which a single bed operates in different substeps at various times. The sequence of transitioning from one substep to subsequent substeps and back to the first is considered a single cycle. The 4- to 24-hour cycle durations common to conventional adsorption approaches require large adsorption systems. The technology platform discussed in the complete paper is based on an alternative approach using rapid cycles that can result in smaller systems to achieve the same separation. The new technology intensifies the separation process, resulting in numerous advantages in addition to cost benefits. Smaller footprint can be crucial when operating in challenging locations (Fig. 1). Smaller systems can enable skid-based project execution, which simplifies fabrication, transportation, installation, and startup. Smaller systems have lower hydrocarbon inventories. Additionally, rapid cycles and novel cycle designs can help expand the operating envelope of adsorption processes while retaining their inherent benefits, such as elimination of solvents.