Preparation Of Pseudoboehmite By Aluminum Alcohol Hydrolysis Method And Related Equipment Design

Pseudoboehmite has excellent properties such as high specific surface area and large pore volume,which can be used as raw materials for the production of active alumina,efficient catalyst carrier,additives,adhesives and adsorbents.In recent years,the process of preparing high purity pseudoboehmite by hydrolysis of aluminum isopropoxide has been developed and gradually industrialized in China.However,in industrial production,there are still some problems in this process,such as low recovery rate of isopropanol,unqualified exhaust emissions,and easy solidification of aluminum isopropoxide.In view of the above problems,this paper first studied the influencing factors of hydrogen release rate in the synthesis of aluminum isopropoxide.Then according to the industrial production design synthesis exhaust absorption equipment.Finally,the effects of synthesis conditions on the carbon residue,crystal phase and pore volume of the product were investigated when aluminum isopropoxide,aluminum sec-butanol and mixed alcohol salt were used as aluminum sources.Specific research contents include:1.Effect of synthesis conditions of aluminum isopropoxide on hydrogen release rate.Using isopropanol and aluminum particles as raw materials,the effects of aluminum purity,aluminum dosage and alcohol dosage on the reaction rate were investigated by changing the reaction conditions.The results show that the hydrogen release rate in the reaction of industrial aluminum(99.7%)and high purity aluminum(99.99%)with isopropyl alcohol is related to the activation area and the concentration of isopropyl alcohol.The activation area in the early stage of the reaction affects the reaction,and the concentration of isopropyl alcohol in the later stage affects the reaction.When industrial aluminum is used as raw material,the fastest hydrogen release rate is 5-10 times higher than that of high purity aluminum under the same conditions due to the corrosion of the original battery.When industrial aluminum reacts with isopropanol,the equation can be established by the influence of aluminum concentration,alcohol amount and raw material amount on the maximum hydrogen release rate per unit volume,and then the maximum hydrogen release rate under given conditions can be calculated,which is of great significance to guide industrial production.2.Design of tail gas absorption tower in aluminum isopropoxide synthesis reaction.Aiming at the problem of hydrogen tail gas containing a large amount of isopropyl alcohol in the synthesis of isopropyl alcohol,an absorption tower with deionized water as absorbent was designed,and the absorbed liquid can be used as aluminum isopropyl alcohol hydrolysate.For the treatment of 1000 m~3/h tail gas,the absorption tower with 0.4 m diameter,4.5 m height and2470 kg/h absorption liquid flow rate was designed.The absorption rate of isopropyl alcohol in tail gas is more than 99%,and the content of isopropyl alcohol in outlet gas is less than 0.1g/m~3,which meets the requirements of tail gas emission.3.Preparation of macroporous pseudoboehmite by aluminol salt solution.Using liquid aluminum sec-butyl alcohol as raw material,the effects of water dosage(molar ratio of water to aluminum sec-butyl alcohol),hydrolysis stirring time,vacuum drying temperature and vacuum drying time on pore volume and residual carbon content were systematically studied.The results showed that the carbon content in the product showed a downward trend with the increase of water dosage,the extension of hydrolysis time,the increase of drying temperature and the increase of drying time.With the increase of water content(1:2-1:5),the crystalline phase transforms from amorphous to pseudo-boehmite,and the pore volume of alumina increases first and then decreases.In addition,self-made liquid mixed aluminum alkoxide,aluminum isopropoxide and aluminum sec-butanol were used as raw materials to compare the properties of the products after hydrolysis.The pore volume of alumina obtained by aluminum sec-butanol was the largest(up to 1.32 mL/g),followed by the product obtained by mixed alcohol salt(1.17 mL/g),and the pore volume of the product obtained by aluminum isopropoxide was the smallest(1.09 mL/g).