Experimental investigation of two-phase separation in T-Junction with combined diameter ratio

T-junctions are often used as partial phase separator to separate two phases gas/liquid feedstock in industrial applications. T-junctions are typically positioned in such a way that two-phase flow entering the T-junction split unevenly between branch and run arm, leaving the gas-rich flow in branch arm and liquid-rich flow in run arm. The T-junctions used in industry are either regular (D-3 = D-1) or reduced (D-3 < D-1) T-junction. There is no design standard available for the design of T-junction. Often, excessive liquid carry-over occurs in the branch arm, resulting in the breakdown of downstream equipment which is not designed to handle excessive liquid. In this study, converging T-junction was designed, developed, and experimentally tested. Converging T-junction was designed with a combination of two diameters D-3 and D-4 in the feedstock. The diameter of the lower pipe D-3 of the branch arm was kept larger than the diameter of the upper pipe D-4. The motivation behind this converging Tjunction was based on the analysis of previous experimental data on regular and reduced T-junction, where a large diameter ratio T-junction resulted in high gas threshold while small diameter ratio T-junction resulted in low peak liquid carry-over. Thus, a converging T-junction will likely possess the best characteristics of both large and small diameter ratio T-junction. Converging T-junction with combined diameter ratios (D-3/D-1, D-4/D-1) of (01, 0.52), (01, 0.20), (0.67, 0.52), (0.67, 0.27) and (0.5, 0.27) were experimentally tested in slug flow regime. The inlet conditions were: Pressure - atmospheric, temperature - 25 degrees C, superficial gas velocities 0.388 <= J(G1) <= 0.620 m/s and superficial liquid velocities 0.252 <= J(L1) <= 0.582 m/s. It was found that the proposed converging T-junction's geometry performed very well. The separation efficiency of 93% was achieved in case of stratifiedwavy flow with not more than 20% of the max. liquid carry-over and above 88% in case of slug flow with less than 35% max. liquid carry-over. This new geometry increased separation efficiency of 5-25% in stratifiedwavy and 20-35% in case of slug flow as compared with conventional T-junction.