19 research outputs found
Design and Control of Glycerol-tert-Butyl Alcohol Etherification Process
Get PDFDesign, economics, and plantwide control of a glycerol-tert-butyl alcohol (TBA) etherification plant are presented. The reaction takes place in liquid phase, in a plug flow reactor, using Amberlyst 15 as a catalyst. The products' separation is achieved by two distillation columns where high-purity ethers are obtained and a section involving extractive distillation with 1,4-butanediol as solvent, which separates TBA from the TBA/water azeotrope. Details of design performed in AspenPlus and an economic evaluation of the process are given. Three plantwide control structures are examined using a mass balance model of the plant. The preferred control structure fixes the fresh glycerol flow rate and the ratio glycerol + monoether : TBA at reactor-inlet. The stability and robustness in the operation are checked by rigorous dynamic simulation in AspenDynamics
A study of L-lactide ring-opening polymerization kinetics
No full textInternational audienceThe paper presents an experimental study of L-lactide polymerization in molten state using as initiator the Stannous Octoate. The experiments were performed in a Haake mixer. The operating temperatures were between 170 and 195°C, the reaction time up to 60 min and monomer to initiator initial molecular ratio between 102 and 5.103. The conversion was determined by using 1H NMR and the molecular weights distributions by SEC. A preliminary mathematical modeling study was also performed, based on experimental data and a previously published reaction scheme
Kinetics of methyl methacrylate combustion over a Pt/alumina catalyst
No full textThe combustion of methyl methacrylate (MMA) over a commercial Pt/γ-alumina catalyst was investigated, in the lean air mixtures specific for the depollution applications. The experiments were performed at temperatures between 150 and 360°C, with MMA concentrations of 460 to 800 ppmv and the gas flow rates between 200 and 300 mL min-1. The results evidenced a negative influence of MMA concentration on the combustion kinetics. A kinetic model of the combustion process was developed, based on the Langmuir–Hinshelwood mechanism, assuming the surface reaction between adsorbed oxygen atoms and adsorbed MMA molecules as the controlling step. The rate expression included the inhibition effects of MMA and water adsorption on the process kinetics. The MMA combustion process simulations evidenced the significant influences of the bulk gas to catalyst particle mass transfer, on the overall kinetics
