Analysis of entrained liquid by use of optical measurement technology

Abstract

Abstract A novel approach to investigate entrainment with aid of a photographic probe enables inline analysis of entrained liquid above column internals at different radial and axial positions. Latest CMOS camera technology allows precise assessment of form and size of droplets at high image qualities and small outer dimensions. A DN 450 cold flow test rig equipped with sieve and fixed valve trays generates droplets over a broad range of gas (1.0–2.75 P a ) and liquid (1.0–20\xa0m3/mh) flows. Results show a strong dependence of droplet sizes on many operation parameters of the column. An increased gas factor of 1.0 P a above the sieve tray reduces the share of droplets below 500\xa0μm from 87% to 18%. Sieve tray experiments show a reduction of droplet size with higher liquid loads. Measurements at greater heights above the fixed valve tray reveal a decrease of the most frequent droplet size (25–50\xa0μm) by factor 2.9. Closer to the column wall, the fixed valve entrains smaller droplets. An extrapolation from local to integral entrainment rates for comparison with the conservative capture tray method achieves satisfactory agreement. Capability of models from literature to cope with the available data are discussed.