Research On Solid Acid Absorption And Recycling Technology Of Ammonia In Cement Kiln Tail Gas

With the improving demands on environmental protection,the treatment and comprehensive utilization of tail gas generated during industrial production has become an important issue for environmentalists.Cement kiln production process will produce a large amount of water vapor,ammonia and carbon dioxide,etc.Recovering the water and ammonia and other components of it is of great significance because it can achieve the recycling of water and ammonia,and also avoid the generation of white plume and prevent pollution to the atmosphere.The recovery of water vapor can be used to form liquid water by condensation,but this method will inevitably lead to the precipitation of ammonia nitrogen along with the condensate,forming ammonia-containing condensate.To realize the comprehensive use of this water,it needs to be further treated with ammonia and nitrogen removal.The existing methods for treating ammonia nitrogen in wastewater are mainly biological and physical-chemical methods,but the treatment cost is relatively high.In order to reduce the treatment cost and realize the comprehensive utilization of water and ammonia nitrogen,this thesis mainly adopts renewable DX03 type solid acid to chemically adsorb and remove the ammonia nitrogen from condensate,and then realize the recovery of ammonia and purification of condensate,so as to achieve the comprehensive utilization of resources and protect the atmospheric environment.Major research efforts include:（1）The adsorption performance of DX03 solid acid on ammonia nitrogen was studied.The experimental results show that DX03 solid acid has good adsorption performance on ammonia nitrogen,high adsorption speed and large adsorption capacity.The dynamic adsorption capacity of DX03 solid acid for ammonia was up to 40.67 mg/g at room temperature.（2）The regenerative performance of DX03 solid acid was studied.The experimental results showed that the DX03 solid acid saturated with 5%formic acid was regenerated by soaking it for 60 min at room temperature under static conditions,and the adsorption performance did not change significantly after 120 consecutive adsorption-regeneration experiments.（3）The adsorption mechanism of ammonia by DX03 solid acid was investigated.The analysis revealed that the adsorption of NH₃ by DX03 solid acids was suitable for fitting with the Langmuir adsorption isotherm model and the pseudo-secondary kinetic model,which indicated that the adsorption was a single molecular layer and mainly occurred by chemisorption.Moreover,particle diffusion and chemical reaction are the main rate-controlling steps in the adsorption of ammonia nitrogen by solid acids.