(298i) Impregnation of Catalysts with Viscous Metal Solutions Using Experiments and DEM Simulations
- Conference: AIChE Annual Meeting
- Year: 2018
- Proceeding: 2018 AIChE Annual Meeting
- Group: Particle Technology Forum
- Time: Tuesday, October 30, 2018 - 10:16am-10:33am
We studied impregnation of Alumina particles with viscous solutions consisting of different concentrations of Nickel Nitrate and Polyvinyl alcohol (PVA, 80% hydrolyzed). PVA solution was used as viscous liquid in our experiments. The viscosities of the PVA solution with different concentrations were measured by a Brookfield DV3T viscometer. Results show that the viscosity of PVA solution is increasing with the increasing concentration.
Langmuir isotherm can be applied to illustrate the adsorption of metal in a viscous solution, where KL is the equilibrium constant and qmax is the maximum adsorption capacity. The two parameters used in the Langmuir model (KL and qmax) need to be determined for the adsorption of a viscous solution on alumina. A series of adsorption experiments were performed for different PVA concentrations. The metal concentration at equilibrium (Ce) was measured by UV-Vis Spectroscopy, and the amount of metal adsorbed (qe) was calculated using a mass balance. Plot 1/Ce vs. 1/qe, a straight fitting line was obtained and the two Langmuir equilibrium parameters were derived from the intercept and slope for different viscosities. Experimental results show that the viscosity slows down the impregnation process. The higher the viscosity the longer it takes to reach the equilibration state. The metal absorbed in the pores depends strongly on the viscosity of the solution. The higher the viscosity the smaller the amount of metal is absorbed. We also found the viscosity of the solution affects the Langmuir equilibrium parameters KL and qmax, which decrease with increasing viscosity.
In addition DEM simulations incorporating these parameters for a viscous solution were considered to reveal the amount of metal absorbed and the uniformity of the particle bed. Using the Langmuir model coupled with the mass balance, the total amount of metal absorbed on solid and the amount metal in the liquid phase can be calculated. Our simulation results show good agreement with the experiments.