Controlled Freeze Zone? Commercial Demonstration Plant Advances Technology for the Commercialization of Sour Gas Resources

摘要

The Controlled Freeze Zone (CFZ~(TM)) technology, developed at ExxonMobil Upstream Research Company, provides for the single-step removal and liquefaction of CO2 as well as other acid gas components present in sour natural gases. It uses a novel three phase (vapor, liquid, solid) separation scheme, taking advantage of the behavior of CO2 to form a pure solid phase as part of a low temperature distillation process, to effect the separation of CO2 from methane. The resulting high pressure liquid bottoms product can then be readily reinjected for geosequestration or enhanced oil recovery purposes. A testing program has been conducted at a 14 MMSCFD CFZ? Commercial Demonstration Plant (CDP) at our Shute Creek Treating Facility in Wyoming, USA. The CDP processed feed streams with CO2 contents ranging from 10 to 70% and H2S contents of 0 to 35% at pressures up to 625 psig. The CDP also demonstrated the advantages of discharging the sour gas components as a high pressure liquid stream by re-injecting the acid gas components via an existing acid gas injection (AGI) facility. This paper will describe how the CFZ? technology works and share highlights of the operational experience of the CFZ? Commercial Demonstration Plant. The effect of CO2 and H2S feed composition and process pressure on CDP operations will be presented. Information on process robustness, lessons from longer term test experiences, and gas dehydration requirements will also be presented.