scholarly journals Systematic Investigations on Continuous Fluidized Bed Crystallization for Chiral Separation

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 394 ◽  
Author(s):  
Erik Temmel ◽  
Jonathan Gänsch ◽  
Andreas Seidel-Morgenstern ◽  
Heike Lorenz
Keyword(s):  
Steady State ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Crystal Size ◽  
Liquid Flow Rate ◽  
Distribution Data ◽  
Steady State Operation ◽  
Mean Size ◽  
Liquid Phase Composition ◽  
Short Time

A recently developed continuous enantioseparation process utilizing two coupled fluidized bed crystallizers is systematically investigated to identify essential correlations between different operation parameters and the corresponding process performance on the example of asparagine monohydrate. Based on liquid phase composition and product crystal size distribution data, it is proven that steady state operation is achieved reproducibly in a relatively short time. The process outputs at steady state are compared for different feed flow rates, supersaturations, and crystallization temperatures. It is shown that purities >97% are achieved with productivities up to 40 g/L/h. The size distribution, which depends almost exclusively on the liquid flow rate, can be easily adjusted between 260 and 330 µm (mean size) with an almost constant standard deviation of ±55 µm.

scholarly journals Empirical correlation for prediction of the elutriation rate constant

2003 ◽  
Vol 7 (2) ◽  
pp. 43-58 ◽  
Author(s):  
Valentino Stojkovski ◽  
Zvonimir Kostic
Keyword(s):  
Steady State ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Rate Constant ◽  
Flow Rate ◽  
Gas Flow ◽  
Particle Density ◽  
Coarse Particles ◽  
Gas Flow Rate ◽  
Mean Size

In vessels containing fluidized solids, the gas leaving carries some suspended particles. This flux of solids is called entrainment, E or carryover and the bulk density of solids on this leaving gas stream is called the holdup. For design we need to know the rate of this entrainment and the size distribution of these entrained particles Rim in relation to the size distribution in the bed, Rib, as well as the variation of both these quantities with gas and solids properties, gas flow rate, bed geometry and location of the leaving gas stream. Steady-state elutriation experiments have been done in a fluidized bed 0,2 m diameter by 2,94 m high freeboard with superficial gas velocities up to 1 m/s using solids ranging in mean size from 0,15 to 0,58 mm and with particle density 2660 kg/m3. When the fine and coarse particles were mixed, the total entrainment flux above the freeboard was increased. None of the published correlations for estimating the elutriation rate constant were useful. A new simple equation, which is developed on the base of experimental results and theory of dimensional analyses, is presented.

Batch Precipitation of Lead Iodide

1994 ◽  
Vol 59 (6) ◽  
pp. 1301-1304
Author(s):  
Jaroslav Nývlt ◽  
Stanislav Žáček
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Crystal Size ◽  
Lead Nitrate ◽  
Lead Iodide ◽  
Constant Rate ◽  
Mean Size ◽  
The Mean

Lead iodide was precipitated by a procedure in which an aqueous solution of potassium iodide at a concentration of 0.03, 0.10 or 0.20 mol l-1 was stirred while an aqueous solution of lead nitrate at one-half concentration was added at a constant rate. The mean size of the PbI2 crystals was determined by evaluating the particle size distribution, which was measured sedimentometrically. The dependence of the mean crystal size on the duration of the experiment exhibited a minimum for any of the concentrations applied. The reason for this is discussed.

Steady-State and Oscillating Behaviour of the Particle Size Distribution in Fluidized Bed Granulation

2001 ◽  
Vol 73 (6) ◽  
pp. 702-702
Author(s):  
Stefan Heinrich ◽  
Mirko Peglow ◽  
Matthias Ihlow ◽  
Markus Henneberg ◽  
Lothar Mörl
Keyword(s):  
Particle Size ◽  
Steady State ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fluidized Bed

Thermal Effects of Gasses in Rapid Thermal Processing

1991 ◽  
Vol 224 ◽  
Author(s):  
K. L. Knutson ◽  
S. A. Campbell ◽  
J. D. Leighton
Keyword(s):  
Steady State ◽  
Numerical Model ◽  
Thermal Processing ◽  
Thermal Effects ◽  
Rapid Thermal Processing ◽  
Radiant Intensity ◽  
Steady State Operation ◽  
Temperature Ramps ◽  
Short Time

AbstractA numerical model has been created for a Rapid Thermal Processing (RTP) system. Experiments have been done to show the validity of the model. The simulations done examine thermal uniformity and stresses incurred by RTP during steady state operation and during short time temperature ramps. It is shown that increasing the radiant intensity at the edge of the wafer reduces stress, compared to a uniform radiant field, in steadystate operation but increases stress during short time temperature ramps.

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