Experiment And Theory Study On Dedusting And Desulphurization With The Bevel Edge Scrubber

Nowadays, particles and SO₂, emitted from the coal-fired industrial boilers, arestill the main air pollutants influencing the urban air quality in China. With thedevelopment of social economy, atmospheric pollution emission standards are strictlyday by day. So we should focus on the research and development of the devicessuitable for Chinese situation. It has a strong theoretical and practical significance.The new bevel edge scrubber （Patent No. CN200420069313.4） has large contact area,high flue gas purification efficiency and excellent heat and mass transfer. In ourdissertation, performance of its resistance, dewatering, dust properties anddesulfurization were studied based on the experiment and CFD simulation. The mainwork and conclusions are listed as follows:Experimental analysis on the new bevel edge scrubber performance. Firsty, thescrubber has good sealing performance by analyzing the air leakage rate（<10%）.Secondly, resistance and dewatering performance were evaluated. When superficialgas velocity was4m/s, the pressure drop reached658Pa. Nevertheless, the bevel edgecomponents will not lead to a substantial increase in pressure drop. When the inletvelocity increased from7.63m/s to17.79m/s, the bevel edge segment increased toapproximately187Pa. Furthermore, the water content in outlet flue gas was less than11g/kg（dry） under the experimental condition.Four surfactants CTAB, SDBS, AEO-9and OP-10were used for washing liquidspreparation respectively. The removal of hydrophobic powdered carbon was carriedout with a bevel edge scrubber. The effects of surfactants, inlet dust concentration,superficial gas velocity, and liquid-gas ratio on dust removal efficiency （η） andpressure drop （ΔP） were discussed. The bevel edge scrubber has high removalefficiency and low pressure drop. Meanwhile, four washing liquids could greatlyimprove the dust removal efficiency. And the washing liquid of AEO-9had theoptimal removal effect. When AEO-9concentration was0.07mmol/L, inlet dustconcentration was5g/m³, L/G was1.0L/m³, and superficial gas velocity was2.5m/s,the removal efficiency reached99.99%. The inlet dust concentration had little effecton ΔP, whereas L/G and superficial gas velocity had much influence on it.Lime washing method was used for desulfuration experiment. The influence onSO₂removal efficiency of SO₂inlet concentration, liquid-gas ratio, superficial gas velocity and Ca/S mole ratio were investigated. The experimental results showed thatthe bevel edge scrubber has good desulfurization performance. Especially in thepresence of bevel edge components, desulfurization performance is greatly enhanced.Desulfurization efficiency increased with the decrease of SO₂inlet concentration andsuperficial gas velocity. Moreover, the best liquid to gas ratio range is3to5. Andwhen Ca/S mole ratio increased from0.9mol/mol to1.7mol/mol, desulfurizationefficiency increased slightly.CFD simulation method was used to visualize the flow field such as velocity field,pressure field, concentration field, and droplet trajectory. It could help us observe thephenomena directly, illustrate the flow characteristics in the scrubber and furtherknowledge the flow field rule. The simulation results showed that the existence ofbevel edge components enhanced gas-liquid mass transfer with a little increase ofpressure drop. Besides, washing liquid has effect on the rectification of gas field. Ingeneral，the simulation results were in good agreement with the experimental resultswith less than10%error.