Novel Benchtop Wheel Loop for Low Dosage Gas Hydrate Inhibitor Screening: Comparison to Rocking Cells for a Series of Antiagglomerants

Abstract

We have designed and built a novel high-pressure wheel loop (volume 200 mL), which allows for easy observation of the fluids inside the whole of the loop. The wheel is mounted horizontally in a cooling bath and is small enough for use as a benchtop device for screening low dosage hydrate inhibitors. The wheel could also be used for other flow assurance issues such as wax inhibition studies. The wheel does not rotate but moves with a Euler motion to cause movement of the fluids around the loop. To increase agitation and reduce the stochastic nature in the hydrate formation process, a few small steel balls were added to the wheel loop. We report here results using this wheel for a series of quaternary ammonium surfactant antiagglomerants (AAs) tested at about 40 MPa at varying AA concentrations and aqueous salinity. The results are compared to tests reported earlier using the same surfactants but in high-pressure sapphire rocking cells under similar test conditions. The two different types of equipment gave the same ranking of AAs but in general we found that the wheel tests required a higher concentration of AA to achieve the same good AA effect at the same test conditions, especially in saline solutions.