The influence of the reactor pressure on the hydrodynamics in a cocurrent gas-liquid trickle-bed reactor

The influence of the reactor pressure on the liquid hold-up in the trickle-flow regime and on the transition between trickle-flow and pulse-flow has been investigated in a trickle-flow column operating up to 6.0 MPa with water, and nitrogen or helium as the gas phase.\ud \ud The effect of the gas velocity and gas density on the hold-up has been explained by means of the modified Galileo number Ga{1+ΔP/(ρlgL)}. At the transition between trickle- and pulse-flow the liquid hold-up is - for a given value of the superficial gas velocity - nearly the same at each gas density. Therefore, at elevated gas densities the transition occurs at higher liquid throughputs. From a comparison of the experiments with water-nitrogen and water-helium it has been concluded that at an equal gas density - for given values of vl and vg - the hydrodynamic behaviour is the same

Hydrodynamics in a pressurized cocurrent gas-liquid trickle-bed reactor

The influence of gas density on total external liquid hold-up, pressure drop and gas-liquid interfacial area, under trickle-flow conditions, and the transition to pulse flow have been investigated with nitrogen or helium as the gas phase up to 7.5 MPa. It is concluded that the hydrodynamics depends on the gas density and not on the reactor pressure. At higher gas densities, the operating region for trickle flow becomes larger while the gas-liquid interfacial area increases only slightly. Pressure gradient and liquid hold-up are considerably affected by gas density and correlations have been derived for these parameters

Characteristics of Spontaneous Musical Imagery

This study follows upon Steven Brown’s 2006 article in The Journal of Consciousness Studies about the “perpetual music track,” a form of constant musical imagery. With Brown’s assistance, a Musical Imagery Questionnaire was developed and administered to 67 participants with the intention of establishing relevant scales for quantifying the presence and extent of spontaneous musical imagery in individuals. In addition to the Musical Imagery Questionnaire, the Six Factor Personality Questionnaire, as well as the Transliminality Scale, which is a measure of openness to psychological material, was used in order to explore the correlations of spontaneous musical imagery to personality constructs. Factor analysis of the responses to the Musical Imagery Questionnaire revealed six meaningful dimensions of spontaneous musical imagery that were labeled as Unconscious, Persistent, Entertainment, Completeness, Musicianship, and Distraction. Participants who scored high on Transliminality also tended to have more persistent, distracting, and unconscious musical imagery. There were also some smaller correlations with other personality variables

Representation of linguistic information determines its susceptibility to memory interference.

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The influence of pressure on the liquid hold-up in a cocurrent gas-liquid trickle-bed reactor operating at low gas velocities

The influence of reactor pressure up to 6.0 MPa on the dynamic liquid hold-up in the trickle-flow regime with superficial gas velocities up to 5.2 cm/s has been investigated for water, ethanol and aqueous 40% ethyleneglycol, with nitrogen as the gas phase. Without gas flow, i.e. single-liquid trickle-flow operation, the reactor pressure has no influence on the dynamic liquid hold-up, which can be well correlated by means of the Reynolds and Galileo numbers. For Rel < 11 the hold-up proportional to Re0.36l and for Rel >> 15 to Re0.55l. This is probably due to a transition between laminar and turbulent film flow. According to the literature the dynamic liquid hold-up is not affected by low gas velocities under atmospheric conditions. The experiments show that in the case of two-phase flow operation at elevated pressures the hold-up decreases at relatively low gas velocities and even more so at higher pressures. This effect has been explained quantitatively by means of the ratio between the pressure gradient and the gravitational force. In addition, the change in the dependence of βdyn on Rel has not been observed anymore: at low Reynolds numbers the hold-up is already proportional to Re0.55l

Hydrodynamics in a cocurrent gas-liquid trickle bed at elevated pressures

Data on design and operation of trickle beds at elevated pressures are scarce. In this study the influence of the gas density on the liquid holdup, the pressure drop, and the transition between trickle and pulse flow has been investigated in a tricklebed reactor operating up to 7.5 MPa and with nitrogen or helium as the gas phase. Gas-liquid interfacial areas have been determined up to 5.0 MPa by means of CO2 absorption from CO2/N2 gas mixtures into amine solutions. \ud A comparison of the results from nitrogen as the gas phase to those of helium shows that at equal gas densities the hydrodynamic states are the same. The gas-liquid interfacial area increases when operating at higher gas densities. When the determined dimensionless interfacial areas agl/as are all within the range 0.25-0.8, the trickle-bed reactor is suggested to operate in the trickle-flow regime. The gas density has a strong influence on the liquid holdup. Due to the higher pressure gradients at elevated gas densities, the liquid holdup decreases noticeably. Besides, the boundary between the trickle-flow and pulse-flow regime shifts toward higher liquid throughputs: the region for trickle-flow operationg becomes larger. For the liquid holdup and the pressure gradient in the trickle-flow regime, correlations derived based on dimensionless numbers can be applied to high-prssure trickle beds