J.C. Charpentier

Chemical kinetics of the reaction of carbon dioxide with amines in pseudo m-nth order conditions in aqueous and organic Solutions

The specific rate of absorption for the gas-liquid system CO2 with cyclohexylamine (CHA) in a toluene solution was measured in a laboratory wetted-wall contactor. This reaction was found to be first order with respect to CO2 and second order with respect to amine. The values of the specific rate of absorption are such that this reaction may be used to determine interfacial areas in reactors working with organic liquids.

A new, improved liquid hold-up correlation for trickle-bed reactors

Abstract Presently available liquid hold-up correlations for trickle-bed reactors are not applicable over wide ranges of system conditions. The new, improved correlation for the liquid hold-up in a trickle-bed reactor presented here, derived from fundamental considerations and a wide-ranging data base of some 5000 hydrodynamic experimental results, is applicable to industrial trickle-bed reactors since it is based on wide variations of all the important variables, including measurements at high pressures. No other previously derived correlations are applicable to high pressure operations. A comparison with recent data on liquid hold-up in co-current upflow of gas and liquid shows that the correlation proposed for high interaction downflow gives a fair estimate of the upflow data, as long as the liquid is not foaming.

A new, improved pressure drop correlation for trickle-bed reactors

Abstract Presently-available pressure drop correlations for trickle-bed reactors are not applicable over wide ranges of system conditions. The new, improved correlation for the pressure drop in a trickle-bed reactor presented here - derived from fundamental considerations and a wide-ranging data base of some 4600 hydrodynamic experimental results - is applicable to industrial trickle-bed reactors since it is based on wide variations of all the important variables, including measurements at high pressures. No other previously derived correlations are applicable to high pressure operations.

Chemical kinetics of the reaction of CO2 with amines in pseudo m–nth order conditions in polar and viscous organic solutions

The specific rate of absorption for five gas-liquid systems: CO2-monoethanolamine (MEA) in ethanol solution, CO2-diethanolamine (DEA) in ethanol, CO2-MEA in ethylenglycol, CO2-DEA in ethylenglycol and CO2-cyclohexylamine (CHA) in ethylenglycol was measured in a laboratory wetted wall contactor. Reactions were found to be first order with respect to CO2 and second order with respect to amine for the first four ones and first order with respect to amine for the last one. The values of the specific rate of absorption are such that these reactions may be used to determine interfacial areas and mass transfer coefficients in gas-liquid reactors working with polar and viscous organic liquids.

Influence of column diameter and high gas throughputs on the operation of a bubble column

Abstract Experimental gas holdup data for several bubble columns including a draught tube are presented. Operation at high gas throughputs up to 14 m s−1 corresponding to the liquid “blowing off” are represented by a diagram describing the different flow configurations in the true emulsion, their evolution and the variation of the gas holdup at distances above the true emulsion.

Interfacial area and liquid side mass transfer coefficient in trickle bed reactors operating with organic liquids

Abstract Interfacial area and liquid-side mass transfer coefficients measured in a 5cm diameter trickle-bed reactor operating with organic liquids are presented d p ≤ 2.4 mm and cylindrical catalyst of size 0.9 mm × 5 mm. A few data concern also 5.9 and 6.4 mm Raschig rings. Gas and liquid flowrates a Mass transfer parameters have been determined by the chemical technique using the carbamation of the reactants cyclohexylamine, monoethanolamine or die results obtained at low gas-liquid interaction with low liquid flowrate are reported for the ionic aqueous systems CO 2 -NaOH and O 2 -Na 2 SO 3 . The variation of the mass transfer data, the gas pressure drop and the liquid holdup with the gas and liquid flowrates show that there exists a strong connection between these parameters. This has led to correlate the with the liquid-solid friction factor within a + 30% accuracy.

Mass transfer in bubble columns operating at high gas throughputs

Experimental interfacial and mass transfer data for several bubble columns including draught tubes are presented. Operation at high gas throughputs up to approximately 10 m s−1 corresponding to transported bed flow is considered. It is shown that, under these hydrodynamic conditions, for a given transfer flux demand the bubble columns require the same energetic cost but can be several times smaller in volume, when compared with other equipment.

Hydrodynamics and gas-liquid-solid interfacial parameters of co-current downward two-phase flow in trickle-bed reactors

Abstract Design of trickle-fixed bed reactors requires knowledge of the hydrodynamics of two-phase co-current downward flow through fixed porous catalytic media and interfacial parameters. Unfortunately, most of the published papers deal exclusively with the hydrodynamics of an air-water system and the determination of gas-liquid-solid interfacial parameters in highly ionic solutions. In this paper, we present some experimental results on the hydrodynamics, pressure drop, liquid holdup, different flow patterns, gas-liquid interfacial areas and liquid-side mass transfer coefficients for organic non-viscous and viscous liquids and liquid-solid mass transfer coefficients with different packings: glass beads (dp = 1.16 × 10−3 m and 4 × 10−3 m), spherical catalyst (dp = 2.4 × 10−3 m) and glass Raschig rings (dp = 6.48 × 10−3 m). Comparison between our values and correlations in the literature will be discussed.

Operating zone and scale up of mechanically stirred gas-liquid reactors

Abstract The aim of the present study was first to propose non dimensional correlations allowing for calculation and scale up of the gas holdup, liquid-side mass transfer coefficient and mechanical power in gas liquid stirred tanks when such parameters as superficial gas velocity and stirring speed are given. Then a comparison of the performances of these equipment with those of bubble column reactors was undertaken.

SELECTIVITY IN G-L REACTIONS CONTRIBUTION TO THE ANALYSIS OF THE SELECTIVITY IN GAS-LIQUID REACTION PART I: LITERATURE AND THEORY

Abstract A careful scrutinity of the literature shows on one hand the crucial industrial problems of selectivity in gas-liquid contactors and on the other hand, reveals the limited number of theoretical and experimental studies on the topic. A theoretical approach is proposed with the scheme A gas→ A liquid A + B→ C A+ C→ D using the film theory equations involving a mass balance between the film and the bulk. An original technique for the solution of the proposed differential system shows the influence of seven nondimensional numbers on the selectivity which is in fact calculated with the help of the concentration profiles in the dissolved gas in the reactant and in the product.