High-Pressure Gas Liquid Separation, Experimental Verification of Separator Internals in Laboratory and Real Fluid Systems

Abstract

Abstract Cameron has a continuous focus on the development of robust, high efficientphase separation internals that has documented performance in real fluidsystems at high pressure. The phase separator internals are designed to meetthe most stringent demands for separation performance in a compact space and istypically used to protect compressors from free liquid. These robust internalswill assure minimum maintenance of downstream equipment is needed therebyreduce the cost and safety issues related to maintenance of the equipmentdownstream the scrubber. These internals will further reduce the need forchemicals as defoamers and demulsifier and can capture the valuable liquid in agas stream prior to transport of gas. The scrubber internals are valuable toolsfor retrofits of existing vessels for increased capacity or to assure removalof liquid in existing vessels. It is also a key element in robust compactsystems when the pressure is high or the space is limited. This paper outlines the development work undertaken for the development of anew generation high efficiency internals which aim is to increase the gascapacity still maintaining acceptable liquid carry over from the scrubber. Thepaper describes the steps taken to verify the performance for real fluidsoperating at elevated pressures. Further it discusses the challenges with highpressure separation of liquid from gas and the error introduced if only testedin low pressure systems using air water for separation. The two latest technologies developed by Cameron for scrubbing is presented. The first technology is a new type of inlet section for scrubbers that unlikemost inlet sections provide a bulk separation of liquid within the inletsection. For the more traditional type of inlets the liquid is separated insidethe scrubber downstream of the inlet section by gravity. The separation ofliquid in the inlet section for the new type of inlet section will unload thescrubber of liquid at high gas rates and thereby extend the scrubber operatingrange. The new inlet section is a vessel internal and it is not an additionalpressure container for the system which makes it is a well suited tool forretrofitting of existing vessels. The inlet is also well suited used for newbuild vessels where the use of the new inlet will reduce the vessel diameterand tan-tan height in a robust two stage scrubber vessel. The new inlet section has been tested prior in a model fluid laboratory, in afull scale real laboratory and the performance has also been tested in fieldfor the first installed commercial unit. The performance for all these testshas been within the expected range and design goals and the test results forthe real unit is presented. The second technology discussed is the development of a new demisting cycloneused at the outlet end of the scrubber as a polishing stage. The developmentrepresents a new generation of the demisting that utilize a new section to helpimprove the performance of the cyclone. The cyclone and the results achieved sofar will be presented in the paper. The removal of liquid in a scrubber can roughly be split in two separateparts. The first part is the inlet section of the vessel that includes the bulkremoval of liquid by gravity in the vessel body. The second part is polishingsection at the gas outlet that is often referred to as the demister section. The inlet section and the demister section have been improved to handleincreased gas loadings for the overall scrubber. The goal for the design of thenew scrubber is to provide a scrubber with the robustness of a traditional twostage scrubber that has bulk separation before demisting for a gas rate that isconsiderably higher than for existing scrubbers.