Study On Circulating Fluidized Bed And The Combination Of Membrane Separation Process

Fluoride,as an essential micronutrient of body,plays an important role to human health.But it can cause fluorosis when we intake excessive element of fluoride for a long time.Most population of countryside live dispersed,while high fluoride water areas that far away from the urban water supply networks distribute widely,if defluoridate by changing the water or the project by supplying centralize water,we should lay pipelines which need huge workload and large investment,so developing an equipment that applys to solve the majority of rural safe drinking water becomes an urgent task which improve rural safety water.Adsorption method operated samplely and maintained lowly has good prospects which has been roported in a number of technologies,About adsorptive fluorine has a lot of research,but more focused on the adsorption material research,the study of adsorption reactor and equipment less reported.This article will circulate in adsorption and membrane separation technology,developed a new type of fluoride in drinking water technology internal circulating fluidized bed adsorption and membrane separation of water fluoride in process,to identify process features,to simulate a high fluoride water as raw water test,first of all,through comparative study of three kinds of adsorption materials to select the most suitable adsorbent,on this basis to carry out the process of test,the main conclusions are as follows:?1?based on the activity of Al₂O₃,active MgO style and modified activated Al₂O₃ three aspects of the contrast experiment,the modified active Al₂O₃ as internal circulating fluidized bed adsorption and membrane separation of water fluoride in the best adsorption material process operation.Considering the powder particle size distribution of material in engineering application range is narrow,the higher the processing difficulty,and 0.042-0.048 mm and 0.048-0.075 mm of k2 values and qmax are smaller,therefore,choose size distribution activity of 0.048-0.075 mm wide Al₂O₃ adsorption materials for the process operation.?2?when the pH value within the scope of 4.5 to 9.5,the selected active Al₂O₃ can achieve very good effect of fluoride,pH at 6.5-7.5 range,in addition to fluorine effect is best.Too high or too low pH value,the activity of Al₂O₃ fluoride effects are significantly reduced;With the increase of temperature,active adsorption quantity increases slightly,Al₂O₃ 35 when 110.39% of the adsorption quantity is 15? ?,the adsorption quantity from 0.40 mg·g-1,25 ?and the adsorption volume is only 0.11mg·g-1,shows less effect of temperature on the adsorption effect of active Al₂O₃.Modification of the active effect of fluoride in the coexistence of Al₂O₃ anion reduced to some extent,the influence of CO₃^2-the biggest influence on the effect of fluoride in SO₄^2-,NO₃^-and Cl^-less fluoride effects on the adsorbent.H₂PO₄^-larger influence on fluorine ion adsorption effect.Competition ion from strong to weak the influence order of CO₃^2-> H₂PO₄^-> SO₄^2-> Cl^-> NO₃^-.?3?by the internal circulating fluidized bed adsorption and membrane separation water fluoride in process of single factor experiment,increasing the air can promote the adsorption of degree,but very limited;Within a certain range increased HRT can promote the adsorption of degree,and then extend water production cycle;Increase in the volume adsorbent additive can improve the reactor adsorption reaction rate,slow the rise of water,which can improve the output of water,but also make the adsorbent total dosing quantity increased;Through the response surface method,determine the internal circulating fluidized bed adsorption and membrane separation of optimum operation parameters of fluoride in water absorbent dosing quantity is 0.5g·L-1,HRT=3.2h.?4?under the condition of optimal operation parameters,when using the native adsorbent,ZCV an operating period of 1.17g·L-1,the MCV is 1.37g·L-1,after five times adsorbent recycling,ZCV=5.13g·L-1,the MCV is 6.69g·L-1;Number of regeneration and the activity of modified Al₂O₃ fluoride in performance is negatively correlated,regeneration,the more the performance of the fluoride in the worse;Membrane fouling was mainly affected by membrane pore jams in the short term,long running pollution mainly filter cake layer.?5?model based on adsorption isotherm and adsorption kinetics model and reactor material balance equation process continuous flow dynamic mathematical model is established.Applications built mathematical model simulation HRT=4h,activated alumina dosing amount of 5g·L-1,air to 1m3·h-1 case process the dynamic change of water fluoride concentration,the results show that the model simulation of the dynamic change of water fluoride concentration process are consistent with the measured curve,analog value relative average error of the measured values is 16.5%,analog value slightly higher than the measured values on the whole.