Abstract
The purity of desalted water by a multistage flash (MSF) evaporator will not be warranted unlessthe entrained brine is sufficiently removed. For an investigation associating with this problem, an instrument to measure the mist concentration and the size distribution has been developed.
A detector of the instrument was directly installed in the 20th flash chamber of a 39 stage MSF test plant having a capacity of 3,000m3/day and successfully offered following data. For one case, the concentration and the weight mean diameter were 0.72×10-4g/l and 70μm respectively, and for another case 2.2×10-4g/l and 120μm respectively. For both cases, the operational conditions were almost same except the brine flow rate in the chamber respectively 800 t/hr (1,300t/m·hr) and 1,000 t/hr (1,700t/m·hr). The 20% increase of evaporation rate resulted in increase of three times mist concentration and twice mist size. The fact indicates that the flash intensity is very sensitive to the mist formation.
