Oxygen Removal in Water Injection: A Life-Cycle Cost Comparison Between Vacuum Degassing and Membrane Deaeration Technologies

Abstract

Abstract This paper aims at making an overall comparison based on life-cycle costs (LCC) between vacuum degassing and membrane deaeration, the two main technologies for removing oxygen from injection water in the energy upstream sector. Traditional degassing technology based on vacuum towers (VT), where oxygen is stripped from liquid water falling on random packing under vacuum conditions, has been compared with membrane deaeration (MDA), a potentially emerging technology in which oxygen moves from the liquid phase through a gas-permeable membrane toward an oxygen-depleted gas stream. The comparison was made based on real projects carried out using vacuum degassing on a wide range of capacities and equivalent membrane deaeration (MDA) configurations obtained by simulating the replacement of the towers and their ancillaries with membrane deaeration. The two deaeration systems were compared in terms of performance, costs/life-cycle costs assessment (LCC), and general characteristics at different operating capacities to identify under which conditions each technology may be preferable. While MDA is already widely applied in several industrial applications, it has still not found its way into the "injection water" market. The study helps identify the conditions under which MDA might be beneficial, in terms of life-cycle costs to the Upstream O&G sector.