Hydrodynamics And Mass Transfer On Sieve-Type Trays Operating In The Spray Regime

The hydrodynamics and mass transfer on sieve-type trays operating in the spray regime has been experimentally studied with an industrial scale simulator.Based on an approach by using R.T.D. method to discriminate the froth regime and the spray regime suggested, the operating conditions for the transition from the the froth regime to the spray regime have been determined and correlated.An automatic system for measuring droplet size distribution has been developed. It comprises an electronic probe sensor, a peak-holding circuit and a microcomputor. Droplet sizes on sieve-type trays operating in the spray regime were measured in real time by the system. The results have been well correlated by the Rosin-Rammler distribution with two parameters dependent on gas loading.The series pulse laser photography and the image analysis technique were introduced into the measurement of the instant velocities of spray droplets on their trajectories. The initial velocities and the projecting angles were calculated from the instant velocities measured. The initial velocity distribution has been inferred by statistical inference to be a normal distribution .A probability model of the movement characteristic of the droplet population has been proposed with the droplet size distribution being taken as marginal distribution and the initial velocity distribution as conditional distribution .An inclined projection trajectory model has been developed for simulating the spray regime. The model does not contain any adjustable parameters and the predicted values by means of it agree well with the experimental data.The mass transfer on the sieve-type trays operating in the spray regime were studied experimentally with ammonia absorption. By simulation calculation, it has been found that the experimental results and the predicted valus agreed quite well.