Oil-Water Separation in a Novel Liquid-Liquid Cylindrical Cyclone (LLCC©) Compact Separator—Experiments and Modeling

Abstract

The hydrodynamics of multiphase flow in a Liquid-Liquid Cylindrical Cyclone (LLCC) compact separator have been studied experimentally and theoretically for evaluation of its performance as a free water knockout device. In the LLCC, no complete oil-water separation occurs. Rather, it performs as a free-water knockout, delivering a clean water stream in the underflow and an oil rich stream in the overflow. A total of 260 runs have been conducted, measuring the LLCC separation efficiency for water-dominated flow conditions. For all runs, an optimal split-ratio (underflow to inlet flow rate ratio) exists, where the flow rate in the water stream is maximum, with 100% watercut. The value of the optimal split-ratio depends upon the existing inlet flow pattern, and varies between 60% and 20%. For split-ratios higher than the optimal one, the watercut in the underflow stream decreases as the split-ratio increases. A novel mechanistic model has been developed for the prediction of the complex flow behavior and the separation efficiency in the LLCC. Comparisons between the experimental data and the LLCC model predictions show excellent agreement. The model is capable of predicting both the trend of the experimental data as well as the absolute measured values. The developed model can be utilized for the design and performance analysis of the LLCC.