Gas/Liquid Scrubber Performance Testing at Field-like Conditions

The Separation Technology Research (STAR) Program joint industry project was initiated in June 2014.  The mission of the STAR Program is to benefit STAR Program participants by providing accurate, applicable performance data for design, characterization, and qualification of separation equipment using a multi-company, collaborative model.  As part of the STAR Program JIP, gas/liquid scrubber performance testing has been conducted on a baseline case (with only inlet vanes) and sets of internals (with inlet vanes, mesh pads, and cyclones) from seven equipment manufacturers.  The scope of this presentation will include an overview of the test procedure and results, including the impact of pressure and liquid volume fraction (LVF) on hydrocarbon gas/oil separation in gas/liquid scrubbers.

Based on input from the STAR Program participants, a testing project was defined, developed, and conducted with the focus of:

• developing standardized procedures for performance testing of scrubber internals

• collecting performance data on gas/liquid scrubbers at field-like conditions

The project plan was developed around an existing scrubber at Southwest Research Institute (SwRI) and the capabilities of SwRI’s Multiphase Flow Facility.  The objective was to conduct testing under field-like pressures and conditions while using hydrocarbon fluids.  Variables included in the test program were gas flow rate, liquid flow rate, and pressure.  The test gas was methane and the test liquid was Exxsol D110 (model oil).  When measured in air at ambient conditions, the nominal Exxsol D110 properties were a density of 0.80 gm/cc, a viscosity of 2.5 cP, and a surface tension of 25.5 dyne/cm.

Standardized procedures were developed for testing gas/liquid scrubber internals. The test section used for the testing, especially the method used for determining scrubber performance, will also be discussed.

The baseline tests have been completed.  The baseline tests showed that the separation efficiency was impacted greatly by test pressure.  In addition, the results for all but one of the LVFs tested correlated in such a way that they almost fell on top of one another.  This was not true for one of the LVFs, where the separation efficiencies were much lower than for the rest of the LVFs, but there was still a strong effect of pressure on scrubber performance at this LVF.

The testing of the seven sets of scrubber internals is currently underway and will be completed in early 2016.  The paper will include a discussion of all of the results, which are not available at the time of this abstract submission.  To date, we see strong effects of pressure and LVF on the performance of the internals tested.

A standardized procedure for measuring scrubber performance has been developed.  In addition, accurate, applicable performance data have been collected that demonstrate the necessity of performance testing at field-like conditions.  These data can be utilized by end users to qualify separation equipment for their field applications.