Study On Desulfurization And Mass Transfer Of Sieve Tray-spray Scrubber

Wet flue gas desulfurization?WFGD?with limestone/gypsum is the most commonly used desulfurization technology in the world.The spray scrubber is the core of a WFGD system.A WFGD system with sieve tray-spray scrubber was established to study desulfurization in the thesis.The gas-liquid two-phase flow on the sieve tray were investigated under the conditions of the superficial velocities range from 1.0 m/s to 1.8m/s,sieve trays with hole diameters range from 5 mm to 40mm and free areas from 20%to 40%.The experimental results showed that pressure drop,froth height of foam layer and liquid hold-up increase with the increase of superficial velocity,but decrease with the increase of free area and hole diameter of a sieve tray.Influences of free area and hole diameters of sieve trays and operation parameters,include liquid-gas ratio,superficial velocity and SO₂ inlet concentration on desulfurization performance were investigated.The results showed that the higher desulphurization efficiency were obtained under the conditions of the pH values range from 5.5 to6.2,the superficial velocity of about 1.45m/s and of the liquid-gas ratio of 16.The desulfurization efficiency of 92%reached using a sieve tray with the hole diameter of 5mm and the free area of 30%.Volume mass-transfer coefficient?K_ya?was calculated by using differential method.It was found that K_ya increases with the increase of pH value and liquid-gas ratio,but decreases with the increase of SO₂ in let concentration.K_ya increases with the decrease of the free area and hole diameters of a sieve tray.However,operating mode was unstable using a tray sieve with small free area and hole diameter.