Experimental And Model Study Of Acid Gas Absorption By Falling Alkaline Droplets

Wet FGD is the main FGD technology. The knowledge of chemical reactions process, especially the SO2 absorption process by falling alkaline droplets are very important for designing the reaction devices, reducing initial investment and operation cost, operating stably and maintaining easily.An experimental platform is designed to study the absorption process by droplets of water, NaOH with different mol concentration and Ca(OH)2 slurry with different mass concentration. There are some advantages to use the platform: (1) It can be used for multi-purpose; (2) The gas velocity can reach a high value of 5 m/s; (3) Methods of analytical chemistry are used to derive result with high precision. With all there advantages, we could get credible data of the absorption process.The second part of the thesis centralizes on the parameters that influence the process. Followed are some results: (1) A model based on penetration theory is used here to calculate the absorption process with a certain penetration interval, which varies from 0.2 ~ 0.6 s in experiments; (2) The main function of droplet diameter is to derive higher absorption surface; (3) Surface regeneration has notable effects on absorption by water, NaOH in low concentration or Ca(OH)2 slurry droplet, while it has minor influence on absorption by NaOH droplets in high concentration; (4) Higher gas velocity causes a longer reaction time, especially to droplets with less diameter, while it has minor influence on droplets' surface regeneration; (5) Smaller droplets are used in spray tower to generate higher absorption surface. For surface regeneration is not obvious in small droplets, high gas velocity should be adopted in the case. While in liquid spray column tower, high gas velocity has less influence in falling time of droplets with bigger diameters. Thus good liquid-gas contact mode should be emphasized here to derive intense surface regeneration, such as coalescence and break-up process.The conclusions derived in the thesis have shown us detailed knowledge of the SO2 absorption process by falling droplets, which could also be applied to industrial application.