Mass Transfer Parameters of O₂ and N₂ in Cyclohexane under Elevated Pressures and Temperatures:  A Statistical Approach

Abstract

The solubility, volumetric mass transfer coefficient, gas−liquid interfacial area, mass transfer coefficient, gas holdup, and bubble Sauter mean diameter for O2 and N2 in liquid cyclohexane were obtained in 4-L gas-inducing and surface-aerated agitated reactors. The modified Peng−Robinson equation of state and the transient gas absorption and photographic techniques were employed. The experiments were statistically designed and the results were statistically correlated with a 95% confidence level. The solubilities for O2 and N2 showed an increase with pressure and temperature, and Henry's law adequately modeled the values. All mass transfer parameters obtained were found to be higher in the gas-inducing than those in the surface-aerated reactor. Mixing speed and liquid height significantly affected the volumetric mass transfer coefficients and gas holdup in both reactors. The pressure and temperature slightly affected the volumetric mass transfer coefficients whereas the bubbles Sauter mean diameter for both gases remained constant at about 0.76 mm.

Hydrodynamic and Mass Transfer Parameters in Agitated Reactors Part I: Critical Mixing Speed, Induced Gas Flow Rate, and Wavy Surface in SARs and GIRs

“…Statistical correlations were also developed for each system investigated in this study using the statistical software package, Minitab Version 9.1 for Mainframe, since statistical correlations, though limited to the systems used, were reported to enjoy high confidence levels and much greater regression coefficients when compared with those of dimensionless correlations (Li et al, 1996;Kim et al, 1994;Tekie et al, 1997b;Fillion and Morsi, 2000). The following general statistical correlation was found for N CRE , N CRI , Q GI, and a wave .…”

“…The Central Composite Statistical Design (CCSD) and analysis technique, similar to that employed by Li et al (1996), Tekie et al (1997b) and Fillion and Morsi (2000) were used to construct an experimental mapping of the parameters, which insured reliable observations; minimum number of experiments; and highly accurate statistical correlations (Montgomery, 1991). The effect of pressure (P), temperature (T), mixing speed (N) and liquid height (H) on the measured experimental data were statistically investigated using the CCSD of four variables (k = 4) at 5 levels.…”

Effects of vapor–liquid mass transfer on feasibility of reactive distillation

“…Physically we can think of changing mass‐transfer resistance (changing Pe numbers) by changing the mass‐transfer coefficients (such as different mixing regimes or gas–liquid velocities) or by changing interfacial area, which could be achieved, for instance, by changing the characteristic bubble size in the system. Changes by an order of magnitude in mass‐transfer coefficient or interfacial area are not uncommon in certain types of equipment, depending on operating conditions (for example, Al‐Dahhan et al, 1997; Sada et al, 1987; Sundaresan and Varma, 1990; Tekie et al, 1997; Veljkovic and Scala, 1988), although such changes are generally possible in laboratory‐scale equipments that are designed to explore the largest possible intervals of operating conditions regardless of economic constraints, which are considered when designing a commercial unit operation.…”

Autocatalytic Cyclohexane Oxidation in a Bubble Column Reactor

“…For the simulations, the surface-mean of the Sauter diameters measured for the five levels (ranging from 1.0 to 1.2 mm) was used for calculating the interfacial area. Henry coefficient and liquid side mass transfer coefficient were taken from Tekie et al (1997) who determined these parameters in bubbly flow and surface-aerated, agitated reactors for the relevant operating conditions.…”