Experimental Study On Dilute Chlorhydric Acid By Desorption And Absorption

Hydrochloric acid is commomly used products in the chemical productionprocesses, on the one hand PVC production of hydrogen chloride usually as a rawmaterial in the chlor-alkali industry,on the other hand, hydrochloric acid is commomlyused in electroplating and steel structure of the acid loution.However, waste emissionsin the use of dilute hydrochloric acid concentration is generally low. Therefore,fromthe perspective of environmental protection and resource recycling,these waste dilutehydrochloric acid for recycling.Since hydrochloric acid forms the highest boilingpoint azeotrope with water, which contains HCl20.24wt%. So it can not be separatedby distillation to obtain hydrochloric acid which concentrations are relatively high.Firstly,20%hydrochloric acid salt desorption and in the desorption of nitrogen as acarrier desorbent was studied,and the effects of salt concentration, nitrogen preheatingtemperature and nitrogen flow Parameters for the desorption solution and equilibriumtime were investigated respectively. Below is the experimental results: when thedesorption feed temperature to the boiling point, the nitrogen preheating temperaturewas75℃, nitrogen flow was4L/min, salt concentration was0.4g/ml, the desorptionsolution can be reduced to1%or less.Secondly, in the reduced pressure control the desorption temperature before boilingof water in order to enhance the desorption of hydrogen chloride gas concentrationwas studied. Below is the experimental results: when the desorption pressure47kPaand the control temperature at the boiling point of80℃before, desorption solutionreached1%or less.Lastly, the third Part of this experiment on the basis of the first Part of theexperiment, zero desorption and absorption process of coupling to concentrate dilutehydrochloric acid was studied, and the effects of absorbent flow rate, nitrogenpreheating temperature and nitrogen flow Parameters for the desorption solutionabsorption solution and equilibrium time were investigated respectively.,Below is theexperimental results: when the absorbent flow rate of25ml/min, nitrogen flow4L/min,nitrogen preheating temperature of75℃, desorption solution reached0.98%andabsorption reached33.18%and HCl absorption rate of91.52%.