Font Size: a A A

A study of moving bed and simulated moving bed separators and reactors

Posted on:1989-11-15Degree:Ph.DType:Dissertation
University:University of MinnesotaCandidate:Fish, Barry BrentFull Text:PDF
GTID:1478390017955855Subject:Engineering
Abstract/Summary:
A moving bed apparatus has been designed, built, and operated as a reactor and a separator. The separator has been operated under conditions for which separation is nearly complete, and also when separation is lost by increasing the feed rate due to the effect of the nonlinear isotherm. This process has been modelled considered infinite and finite mass transfer rates and an operating optimization diagram has been constructed for the case where the ratio of linear adsorption constants is 1/2. {dollar}sigmasb{lcub}rm i{rcub}{dollar} is a parameter which represents the solids carrying capacity divided by the gas phase carrying capacity under linear isotherm conditions. A is assumed to be the least strongly adsorbed component. Production rate can be increased by operating at {dollar}sigmasb{lcub}rm A{rcub}{dollar} {dollar}>{dollar} 1 without sacrificing product purity due to the beneficial effects of competitive adsorption below the feed. A maximum bound of {dollar}sigmasb{lcub}rm A{rcub}{dollar} equal to the ratio of linear adsorption constants has been predicted by equilibrium theory arguments, and has not been disproved by the finite mass transfer model results.; The hydrogenation of mesitylene to 1,3,5-trimethylcyclohexane has been investigated at a temperature and H{dollar}sb2{dollar} concentration for which equilibrium conversion if 0.66. A top feed configuration can give a conversion near 100% with product purity near 100% at low feed rates and properly tuned solid and gas flow rates. Higher production rates can be obtained without sacrificing purity by lowering the feed point. Revisions have been suggested for the ideal reactor model which include a finite mass transfer resistance and a 2-site adsorption model, separating the effect of adsorption on the catalyst support and adsorption on the catalytically active sites.; A simulated countercurrent contactor has been designed, built, and tested isothermally by separating propylene and dimethylether at room temperature on chromosorb 101. The ratio of retention times is about 2. Optimum switching time and maximum product purity were found as a function of feed rate. At low feed rates, when the isotherm is nearly linear, purities near 100% for the most strongly adsorbed component product stream and around 93% for the least strongly adsorbed component stream have been achieved.
Keywords/Search Tags:Moving bed, Finite mass transfer, Product
Related items