Fluidised-Bed Catalytic Reactors

Mahechi-Botero et al. recently reviewed forty fluidised-bed catalytic reactors. Each design uses different assumptions so simulation methods vary. The review allows users to choose a suitable simulation model for their process and reactor.

Microencapsulation of Oils Rich in Polyunsaturated Fatty Acids

Fluidised bed coating is one of the microencapsulation techniques to minimise core material and oxygen diffusivity. Drusch and Mannino reviewed approaches where the core material releases to specific targets.

Powder Flow Dynamics

Krantz, Zhang and Zhu carried out fluidised bed expansion to characterise powder flow under stress at 22-31 μm medium particle size. They also did cohesion tests to find that flow properties depend on stress state.

Polycarbonate Hydrolysis in Earth-Alkali Oxides and Hydroxides

Grause et al. described polycarbonate (PC) 300-500°C hydrolysis to make bisphenol A (BPA), phenol and isopropenyl phenol(IPP). The catalysts compared were MgO, CaO, Mg(OH)₂ or Ca(OH)₂. This option to treat used PC results in less residue.

Anionic Surfactant Photooxidation in three-phase fluidised bed reactor

Nam et al. performed sodium lauryl sulfate photooxidation in three-phase fluidised-bed reactor. The catalysts were immobilised TiO₂ and SiO₂ porous support. The process conditions included air flow rate, catalyst concentration, initial surfactant concentration, light source and pH. The Korean scientists found that superficial air velocity affected reaction rate. The reaction followed the Langmuir adsorption model and did better under acidic condtions.

Hydrogen Production from Starch-Wastewater with Bio-granules

Akutsu et al. fermented starch-wastewater with bio-granules to produce hydrogen in an upflow anaerobic sludge bed. The parameters were hydraulic retention time (HRT), pH and starch concentration. The maximum stable hydrogen yield was 1.7 mol H₂ mol^-1 glucose. The granule had a 0.5-4.0 mm diameter consisting pretreated methanogenic nuclei. Formic or lactic acid presence signified process deterioration.

Reference

Mahecha-Botero, A., Grace, J.R., Elnashaie, S.S.E.H. & Lim, C. J. (2009). Advances in modelling of fluidized-bed catalytic reactors: a comprehensive review. Chemical Engineering Communications. 196(11), 1375-1405. doi:10.1080/00986440902938709

Drusch, S. & Mannino, S. (2009). Patent-based review on industrial approaches for the microencapsulation of oils rich in polyunsaturated fatty acids. Trends in Food Science & Technology. 20(6-7) 237-244. doi: 10.1016/j.tifs.2009.03.007

Krantz, M., Zhang, H. & Zhu, J. (2009). Characterization of poder flow: Static and dynamic testing. Powder Technology. 194(3), 239-245. doi:10.1016/j.powtec.2009.05.001

Grause, G., Sugawara, K., Mizoguchi, T. & Yoshioka, T. (2009). Pyrolytic hydrolysis of polycarbonate in the presence of earth-alkali oxides and hydroxides. Polymer Degradation and Stability. 94(7), 1119-1124. doi:10.1016/j.polymdegradstab.2009.03.014

Nam, W., Woo, K. & Han, G. (2009) Photooxidation of anionic surfactant (sodium lauryl sulfate) in a three –phase fluidise bed reactor using TiO2/SiO2 photocatalyst. Journal of Industrial and Engineering Chemistry. 15(3), 348-353. doi:10.1016/j.jiec.2008.11.006

Akutsu, Y., Lee, D.Y., Chi, Y.Z., Li, Y.Y., Harada, H. & Yu, H.Q. (2009). Thermophilic fermentative hydrogen production from starch-wastewater with bio-granules. International Journal of Hydrogen Energy. 34(12), 5061-5071. doi:10.1016/j.ijhydene.2009.04.024.

Supercritical Fluid Processes

Chemical processes could be hazardous, expensive and contribute to pollution. Supercritical fluids are an alternative investigated to reduce and eliminate industrial pollution and manufacturing costs. The two examples are supercritical water in biomass refinery and supercritical carbon dioxide to replace organic solvents.
The water processes in the figure below are divided into:

1. Incineration
2. Gasification,
3. Separation,
4. Solubilization,
5. Hydrolysis, and
6. Conversion Reactions.

The carbon dioxide processes are:

• Extraction,
• Organic Synthetic Reactions,
• Catalysis,
• Biotechnology,
• Polymerization,
• Particle Engineering,
• Textile Dyeing, and
• Advanced Material Manufacture.

Supercritical Fluid Carbon Dioxide

Category	Examples
Extraction	Coffee decaffeination Fatty acid refinery Flavour isolation from hops Herbal products
Organic Synthetic Reactions	Friedel Crafts Diels-Alder Aldol Claisen rearrangement Michael addition Kolbe-Schmitt reaction
Catalysis	Fisher-Tropsh Hydroformylation Hydrogenation Heck reactions Suzuki reactions Oxidations Alkylation reactions
Biotechnology	Enantioselective chemical transformations Lipase catalyzed esterifacation Enzyme in Packed column continuous flow with toluene
Polymerization	Amorphous fluoropolymers Polysiloxanes Some hydrocarbon polymers Polybutylacrylate Polystyrene
Particle Engineering	Drug delivery system Rapid expansion of supercritical fluid solutions (RESS) Supercritical fluid anti-solvents (GAS) Polymer supercritical fluid extraction of emulsions (PSFEE)
Textile Dyeing	Dye solvent for polyesters, nylon, silk, cotton and wool
Advanced Material	Ionic liquid as electrolytes in batteries, lubricants, plasticizers, extraction, inorganic and biochemical catalysis Speed up, dry or replace aerogel fabrication Polyimides infusion

References

Ramsey, E., Sun, Q.B., Zhang, Z.Q., Zhang, C.M. & Gou, W. (2009). Mini-review: Green sustainable processes using supercritical fluid carbon dioxide. Journal of Environmental Sciences-China. 21(6), 720-726. DOI:10.1016/S1001-0742(08)62330-X

Arai, K., Smith, R.L. & Aida, T.M. (2009). Decentralized chemical processes with supercritical fluid technology for sustainable society. Journal of Supercritical Fluids. 47(3), 628-636. DOI:10.1016/j.supflu.2008.11.008