Gas-liquid mass transfer characteristics in a bubble column with suspended sparingly soluble fine particles

Abstract

2. The experimental results from a simulated 3-stage countercurrent extraction scheme were qualitatively predicted by the theoretical calculations. Gasohol with 90 to 96% ethanol recovery can be produced at room temperature if a 90 wt % ethanol feed is used.3. Solvency of the extractive solvent is directly proportional to the aromatics content in the solvent. However, the higher the solvency, the higher the water content in the product gasohol. Even a minor amount of water in gasohol will create a phase separation in colder climates.4. Experiments were also successful for producing gasohol in a 1.5-in. i.d. continuous column. Gasohol with 91.4% ethanol recovery was produced at 108 °F with unleaded gasoline. Increasing extraction temperature from 75 to 108 °F, the water content in gasohol increased only 0.1 wt %. The ethanol recovery can be further improved by use of a longer extraction column.5. Both molecular sieve absorption and chemical treatment can be effectively used to remove the minor amount of water in the product gasohol. The economics of these treatments need to be investigated.6. Instead of extraction, contacting and cooling is an alternative method for producing gasohol. Stabilized wet gasohol can be made by simply mixing 85-93% ethanol with unleaded gasoline at an appropriate temperature.The homogeneous mixture is then cooled to allow equilibrium and phase separation. Again, the economics of this process need to be studied. 7 pm in average size. Such mass transfer parameters as volumetric liquid-side mass transfer coefficient kL°a, specific gas-liquid interfacial area a, and hence liquid-side mass transfer coefficient kL°w ere determined under various electrolyte concentrations, solid concentrations, and gas flow rates, and kL°a could be correlated by the gas flow rate. The volumetric gas-side mass transfer coefficient k^a was determined and correlated by the gas flow rate. The enhancement factors during absorption of dilute carbon dioxide into aqueous calcium hydroxide slurries were compared with the theoretical predictions based on the film theory incorporating a finite slurry concept.

Absorption of Carbon Dioxide in a Bubble-Column Scrubber

“…Both procedures show that the data are close together, larger data points for precipitation and smaller data points for no precipitation. The values obtained in this study were higher than those reported by Fan (1989), as shown in the parallelogram, while the values were close to the values reported by Sada et al (1985). On the other hand, the trend in our data, extrapolated into smaller gas-superficial velocity, was higher than that reported in Sanchez et al (2005 …”

“…The exponent of u in here was 0.22, which is lower than 0.75 reported in the literature (Sada et al, 1985;Botton et al, 1980). Due to this, the individual mass-transfer coefficients, k L a and k G a, could be determined when the operating conditions were given; and hence, the overall mass-transfer coefficient was estimated by Equation (45).…”

“…The liquid may flow through the column either with or against the gas flow. Investigations of bubblecolumns from the viewpoints of both environmental problems and industrial use can be found in the literature (Juvekar & Sharma, 1973;Sada et al, 1985;Sauer & Hempel, 1987;Okawa et al, 1999;Chen et al, 2002;Hamid & Jones, 2002;Lapin et al, 2002). Bubble column reactors are widely used in the chemical, petrochemical, biochemical, and metallurgical industries (Degaleesan & Dudukovic, 1998).…”

Effect of flow rate and CO2 content on the phase and morphology of CaCO3 prepared by bubbling method

“…(1)) [10,11]. After the dissolution of CO 2 , the freshly formed CO 3 2À reacts with Ca 2+ and forms the temporary resultant of amorphous calcium carbonate, which is an unstable form and often described in spherical shapes of diameter lower than 1 mm.…”

New Approaches for Theoretical Estimation of Mass Transfer Parameters in Both Gas-Liquid and Slurry Bubble Columns

“…Cho and Wakao (1988) carried out experiments on stripping of five organic solutes with different Henry's law constants in a batch bubble column with water and they proposed two correlations (for single nozzle and for porous tube spargers) for k G a prediction. Sada et al (1985) developed also correlation for k G a prediction. In the case of slurry bubble columns, the authors measured k G a by using chemical adsorption of lean CO 2 into NaOH aqueous solutions with suspended Ca(OH) 2 particles and they developed a correlation.…”