SS: High Pressure Gas-Liquid Separation: CO_2 Droplets: One-Component Two-Phase System as Model Fluid for High-Pressure Hydrocarbon

摘要

In the process of performing either scientific experiments or research and development related to the design and optimization of high pressure separator units, both laboratory experiments and tests in prototypes are needed. In order to emulate the low interfacial tensions often experienced in high pressure hydrocarbon systems, the utilization of carbon dioxide (CO_2 ) as model fluid is studied. The present work describes how the CO_2 system behaves at saturation conditions. It describes this system and compares it with traditional laboratory systems and real fluids (from the field). CO_2 at saturation pressure under normal temperatures presents an interesting system with low interfacial tension, below 3 mN/m, while the liquid/gas density ratio is around 3. The availability of the fluid (CO_2 ) in research centers and academia is high. When planning a matrix of experiments as part of a data base of reproducible laboratory fluids, the present system is an independent base vector ideal for studying the high Weber/low Reynolds number regime. Results show that it is possible to obtain streams of droplets for droplet experiments. The mean diameter in the studied regime with the utilized nozzle was of the order of 100 microns, while the smallest droplets possible to track with the presented technique were around 40 microns. Droplet/wall collision experiments were focused in this work. Both coalescence and bouncing were observed on both dry and wet walls. The absence of real fluid experiments at laboratory conditions generates a lack of basic knowledge about what is happening in real scrubbers. This system is proposed to be representative for a part of the flow/property region of interest in real scrubbers. This basic knowledge is fundamental when designing separation units at high pressures for gas processing stages such as sub sea gas separation concepts.