Study On The Production Of Anhydrous Alcohol On The Modified Cassava Adsorbents By The Fixed Bed Adsorption

Anhydrous alcohol is a kind of renewable fuel, and it could be used in the special alcoholengine, or be used directly as a mixture with gasoline according to certain proportion, incondition that no modification was made to the original gasoline engine. However,alcohol-water mixture can not be changed to anhydrous alcohol using normal distillationbecause of the azeotropic point at atmospheric pressure. The molecular sieve adsorption wasthe main process to produce anhydrous alcohol, but the production process for the molecularsieve accompanied much energy consumption. In this research, the biomaterial adsorptionwas adopted, and the modified cassava was used as adsorbents to produce anhydrous alcohol.The research was about the modifying method of cassava adsorbents. The effect ofhydrochloride acid concentration, reaction time and temperature in modifying experiment wasanalysed by orthogonal method, therefore the best modifying condition was confirmed. Thecharacterization of the cassava adsorbents and modified cassava adsorbents was measured byscanning electron microscopy(SEM), the specific surface area of the modified cassavaadsorbents was calculated based on the BET two parameter theoretics and the adsorptionisotherm of water was analysed with the Sircar model prediction. The production capacity andadsorption performance of the modified cassava adsorbents was investigated in the fixed bedadsorption experiment, through the experimental data of penetrating curves, temperaturecurves at different bed height and the moving speed of adsorption wave etc. in differentoperating conditions.The experimental results indicated that: the excellent combination of modified conditionsin making modified cassava adsorbents with acid-process was hydrochloric acid concentrationat 6 %, reaction time of 10 hours, reaction temperature at 45℃. The modified cassavaadsorbents exhibited much better adsorption performance than the cassava sorbent. Theadsorption isothermal of water in the modified cassava adsorbents belonged to the type IIisothermal, and the specific surface area of the modified cassava adsorbents was 401.8 m2/gthrough the calculation of the BET model. The production capacity of the modified cassavaadsorbents was 0.233-0.308 g/g in the fixed bed adsorption process. The modified cassavaadsorbents was full of promise good prospect for industrial application and the producting offuel ethanol through fixed bed adsorption. The appropriate higher bed height and slowerspeed of the vapor conduced to the higher productivity of the modified cassava adsorbents. Inthe industrial production, the operating conditions should be chosed according to specificrequirements. The process of the fixed-bed adsorption on the modified cassava adsorbents forproducing anhydrous alcohol was feasible because of the good adsorption ability of themodified cassava adsorbents. The advantages of using cassava as the material of adsorbentsswere that the price of cassava is low and the energy consumption in the production is low, inaddition, the modified cassava adsorbents could be used as the raw material of thefermentation to produce alcohol when out of use. The production of anhydrous alcohol onthe modified cassava adsorbents by the fixed bed adsorption had a good industrial applicationprospect.