Study On The Dispersion Effect Of Nano-Ni In Ethanol Solution In A Rotation Packed Bed

Nano-catalysis technology is an emerging forefront technology in industrial catalysis and has the advantages of high efficiency,mild operation conditions and easy recovery of the catalyst,etc.However,nano-catalyst with high specific surface and surface energy is very easy to cause the aggregation,which leads to the large average particle size(Dn)of nano-catalyst and thus hinder the catalytic process.Therefore,how to achieve a good dispersion of nano-catalysis in reaction media becomes the key to the development of nano-catalytic process.Due to the strong micromixing of RPB,the rotation packed bed(RPB)was carried as experimental device to study the dispersion effect of nano-Ni in the ethanol solution in this paper,and the effects of various operation conditions on the dispersion effect were explored in RPB and in stirred tank reactor.Additionally,an empirical correlation of DN was established.The main results are as follows:1.Investigation on the dispersion effect of nano-Ni in ethanol solution in the STR.The experimental results indicated that DN decreased with an increase of stirring speed and stirring time,and it first decreased and then increased with an increase of volume fraction of cinnamaldehyde(CAL),temperature and nano-Ni content.The DN was smaller at acidic or alkaline condition than that at neutral condition.The dispersed nano-Ni with a DN of 2.1 ?m was obtained under the optimal operating conditions of a nano-Ni content of 10 g/L,a liquid volume of 300 ml,a stirring speed of 1500 rpm,a stirring time of 2 h,a temperature of 403 K and a pH of 13.2.Investigation on the dispersion effect of nano-Ni in ethanol solution in the RPB.The experimental results indicated that the average particle size of the dispersed nano-Ni(DN)decreased with an increase of flow rate,rotation speed and cycle time,and it first decreased and then increased with an increase of volume fraction of CAL and nano-Ni content.The DN was smaller at acidic or alkaline condition than that at neutral condition.The dispersed nano-Ni with a DN of 1.2 ?m was obtained under the optimal operating conditions of nano-Ni content of 10 g/L,a cinnamaldehyde's volume fraction of 20%,a flow rate of 540 ml/min a stirring speed of 2850 rpm,a cycle time of 2 h,a temperature of 293 K and a pH of 3.Additionally,an empirical correlation of DN was established as the following equation and the calculated values of DN agree well with the experimental values with a deviation within ±10%.DN= 70.161L-0.051N-0.363t-0.194p0.017C-0.012...