Oil-Water-Gas Three-Phase Separation in Multitube T-Junction Separators

Abstract

Multitube T-junctions can be used as an oil-water-gas pre-separator in the oil and gas industry. In this paper, the mixture model, coupled with the k-ε turbulent model, was applied for a simulation of the oil-water-gas three-phase flow characteristics in the multitube T-junction separator. The oil droplet size ranged from 1 to 4 mm. The water content ranged from 5% to 20% and the gas content from 3% to 25%. According to the phase separation results for different droplet sizes, it was found that, as the oil droplet size increased, the water content at the water outlet initially increased and then tended to be stable. Therefore, it was necessary to increase the oil droplet size through corresponding measures before flowing into the T-junction for separation. For the separator with an inner diameter of 50 mm, the oil content at the inlet had a great influence on the water-oil separation performance, and the water-oil separation performance was obviously improved as the oil content decreased. Owing to increased residence time, the oil content had little influence on the water-oil separation performance when the separator with an inner diameter of 100 mm was applied. Moreover, for the separator with an inner diameter of 100 mm, the oil content had little influence on the degassing effect, and more than 90% of the gas could be discharged from the gas outlet. The separation performance of the multitube T-junction separator became worse as the inlet gas content increased.

Technologies and Applications of Pipeline-type Oil-gas-water Separation

“…Turbulence models in multiphase flows are much more complex than single-phase flows, and the  − k model is the most widely used. For cases where the layered flow and phase density ratio are close to 1, the turbulence characteristics can be well captured by using the mixed turbulence model [2] .…”

“…Since 2000, the scientific research institutions headed by the Institute of Mechanics of the Chinese Academy of Sciences have carried out the innovation of high-efficiency oil-gas-water separation technology through in-depth research on the multiphase flow mechanism of oil, gas, and water, put forward the concept of pipeline separation, and developed into a series of pipeline separation devices and technologies with spiral pipe, T-shaped pipe, swirl pipe, air floatation pipe, and coalescing pipe as the core, breaking through the traditional separation method based on gravity settlement of large tanks in oilfields [1,2,3] .…”

Review of Factors Affecting the Phase-Redistribution in the Branching T-Junction

“…Some use Biomass as fuel and some use gas extracted from the wells for power generation [10]. While separating crude oil from the wells, a multiphase mixture of water, gas, oil, solids and minerals is produced [11,12]. Tjunctions are employed along with gas scrubbers to facilitate phase separation.…”