Sucrose Crystallization in Vibrated Bed Process, Unusual Crystallizer Configuration

2017 ◽  
Vol 899 ◽  
pp. 77-82
Author(s):  
Davi Batista Quintino ◽  
Ricardo Amâncio Malagoni

Through yield and Sauter mean diameter, the sucrose crystallization was studied in vibrated bed equipment, in which, supersaturation degree, dimensionless vibration number and crystallization time were independent variables. A central composite design with seventeen trials was performed in order to ascertain the influence of each variable in both responses, the crystallization temperature and the amount of seeds were kept constant. The crystallization vibration system differs from the usual configuration, consisting of two perforated discs made of stainless steel, one loop and three aluminum rings. By canonical analysis, it was obtained the operating condition which maximizes the yield and average crystal size. Surface responses were also obtained according to the relevance of each variable, in which were evidenced the high supersaturation and vibration influence for both factors, the high quadratic term of all variables on the crystal yield, and also highlights the great interaction between supersaturation and the dimensionless vibration number.

2021 ◽  
Vol 57 (4) ◽  
pp. 333-342
Author(s):  
Trung Huu Nguyen ◽  
Tran Nguyen Minh An ◽  
Mahboob Alam ◽  
Duc Hoai Tran ◽  
Nghi Tran ◽  
...  

The goal of the research is to develop an experimental mathematical model of pan coating process effect on the biodegradable polymer and to determine optimal process parameters. The polymer solution was conducted with phosphated di-starch phosphate, polyvinyl alcohol, and polyacrylic acid and performed as material coating for the controlled-release urea fertilizer. The image analysis method has been used to determine the particle size distribution, Sauter mean diameter of the particle and layer thickness that is novel. The central composite rotatable design has been selected to determine the regression models of the process, which described the relationship between two objective variables as layer thickness, release time with angle of pan, spray flow, and coating time. The statistical analysis results indicate the fitness of model.


2018 ◽  
Vol 116 (1) ◽  
pp. 110
Author(s):  
Lixiong Shao ◽  
Jiang Diao ◽  
Wang Zhou ◽  
Tao Zhang ◽  
Bing Xie

The growth behaviour of spinel crystals in vanadium slag with high Cr2O3 content was investigated and clarified by statistical analyses based on the Crystal Size Distribution (CSD) theory. The results indicate that low cooling rate and Cr2O3 content benefit the growth of spinel crystals. The chromium spinel crystals firstly precipitated and then acted as the heterogeneous nuclei of vanadium and titanium spinel crystals. The growth mechanisms of the spinel crystals at the cooling rate of 5 K/min consist two regimes: firstly, nucleation control in the temperature range of 1873 to 1773 K, in which the shapes of CSD curves are asymptotic; secondly, surface and supply control within the temperature range of 1773 to 1473 K, in which the shapes of CSD curves are lognormal. The mean diameter of spinel crystals increases from 3.97 to 52.21 µm with the decrease of temperature from 1873 to 1473 K.


Author(s):  
Pranabendu Mitra ◽  
Kyu -Seob Chang ◽  
Dae-Seok Yoo

Kaempferol, a strong antioxidant, was extracted from Cuscuta reflexa (a medicinal plant) using supercritical CO2 and separated using thin-layer chromatography, column chromatography and HPLC analysis. A rotatable central composite design was used to determine the influence of process variables and arrive at optimal processing conditions in the supercritical CO2 extraction process of kaempferol. The kaempferol yield was effectively modelled as a function of the independent variables (temperature, time and pressure). The kaempferol yield increased with the increasing of temperature and time and decreasing of pressure of the supercritical CO2 extraction process. The predicted kaempferol yield at the optimum point was 52.92 µg/g and the optimum conditions were 50.7°C for 132.6 min and 15.9 MPa.


2020 ◽  
Vol 36 (6) ◽  
pp. 1088-1095
Author(s):  
Le Thi Bich Nguyet ◽  
Vinh Tien Nguyen

In this study, we developed a starch-gelatin film incorporated with synthesized curcumin to be used as a pH-sensitive smart material for food packaging. The film-forming mixture contained five components: starch, gelatin, glycerol, acetic acid and curcumin. The interactions of the components and their effects on the film properties were investigated by using response surface methodology with central composite experimental design. The results showed impacts of the contents of these components as independent variables on tensile strength, elongation at break, Young’s modulus and solubility of the films. The contents of starch, gelatin and glycerol significantly affect these properties, while acetic acid and curcumin do not (p<0.05). Also, it was shown that the incorporation of curcumin provided the film with the capacity to sense pH changes from neutral to basic (yellow at pH ≤ 8 and orange-red at pH ≥ 9).


2014 ◽  
Vol 881-883 ◽  
pp. 29-34
Author(s):  
Ye Zhang ◽  
Ming Qiang Chen ◽  
Jun Wang

Optimization of chromium sulfate catalyzed conversion conditions of xylose into furfural was studied by response surfacemethodology (RSM). A central composite design (CCD) was used to determine the effects of independent variables, including temperature (120-160°C), time (30-150min), catalyst loading (1-5mmol) and moles of xylose (2.5-12.5mmol) on furfural yield, xylose conversion and solid residue. The surface response analysis revealed that temperature, time, catalyst loading and moles of xylose had a strong influence on the furfural yield, whereas moles of xylose was found to be notsignificant for xylose conversion. The solid residue was affected by temperature, time and moles of xylose. The maximumpredicted furfural yield was 45.07% at temperature of 150°C, time of 12min, catalyst loading of 2 mmol and moles of xylose of 10mmol. Under this condition, xylose conversion could be reached 100%.


2014 ◽  
Vol 625 ◽  
pp. 920-923 ◽  
Author(s):  
Halifah Pagarra ◽  
Roshanida Abd Rahman ◽  
Rosli Md. Illias ◽  
Nor Azah Ramli

A central composite design was employed to optimize the extraction of pectin from Nephrolepis biserrata leaves. The independent variables were pH (1.5 to 2.5), extraction time (60 to 120 minutes) and temperature (60oC to 100oC). The combined effect of these variables on yields of pectin was investigated. The results showed that the yield of extracted pectin ranged from 3.76% to 8.50% (w/w, based on dry weight of Nephrolepis biserrata leaves). The optimum condition for the yield of pectin extraction was predicted at pH (1.5), extraction time (76.25 minutes) and temperature (100oC). Under the optimum condition, the actual pectin yield was 8.18%, which was below the predicted extraction condition of 8.316 %. The characteristics were 47.52% galacturonic acid and 83.71% degree of esterification. Keyword: Nephrolepis biserrata leaves, Extraction, Pectin, RSM, Characterization.


Author(s):  
M. M. Elkotb ◽  
M. A. Elsayed Mahdy ◽  
M. E. Montaser

A detailed investigation of the effect of nozzle/needle diameter ratio, normal fuel area, swirler degree, air pressure, fuel pressure on flow number, cone angle and droplet size distribution of external mixing twin fluid atomizers is given in this paper. Forty atomizers have been constructed to prevent mutual effect of various parameters. Flow number and cone angle are found to increase with nozzle/diameter ratio, and to decrease with the increase of air pressure. Optimum fuel flow is obtained at swirler angle 30-deg, while cone angle increases with increase of swirler angle. Sauter mean diameter decreases with the increase of air pressure and decrease of fuel pressure. Suitable functions are derived for droplet size distribution, Sauter mean diameter, and flow number. They are suitable to predict the geometry of the atomizer and to be used also in a prediction model for the calculation of fuel concentration and heat release.


Author(s):  
A. Dalili ◽  
S. Chandra ◽  
J. Mostaghimi ◽  
H. T. Charles Fan ◽  
J. C. Simmer

A compressed air sprayer was used to spray model paint onto two glass substrates at the same time. Afterwards, one glass substrate was placed on a LED light source and still photographs were taken from the top using a DSLR camera with a timer system. The other substrate was put on a balance to record weight. Pictures and weight measurements were taken at 5 second intervals for 15 minutes. The sprayed film thickness was varied. The pictures were analyzed using ImageJ software. Bubble Count vs. Time, Sauter Mean Diameter (SMD) of Bubbles vs. Time as well as Weight vs. Time was plotted. It was seen that the pace of weight loss was faster for thinner films. The rate of bubble escape also depended on film thickness. It took a longer time for thicker films to lose the bubbles entrapped in them. In the first 30 seconds, large bubbles escaped due to buoyancy forces and afterwards surface-tension driven flows became dominant. There was also a lot of bubble movement in thicker films. The effect of gravity was studied as well. Gravity did not affect the bubble escape rate since a downward facing film had the same bubble count as an upward facing film confirming that bubble motion was not due to buoyancy forces alone. However, the SMD of bubbles in a downward facing film was larger than an upward facing film. Buoyancy is not a factor in bubble escape from the downward facing film and only surface-tension driven flows play a role.


Author(s):  
Lee G. Dodge ◽  
Clifford A. Moses

A comparative study has been performed of the drop-size distribution of sprays of emulsified and neat distillate-type aviation fuels at elevated temperatures (308K to 700K) and pressures (101 kPa to 586 kPa). All drop-size data were obtained with a Malvern Model 2200 Particle Sizer based on the forward angle diffraction pattern produced by the drops when illuminated by a collimated HeNe laser beam. Fuels included a standard multicomponent jet fuel, Jet-A, and a single component fuel, hexadecane, in both neat form and emulsified with 20 percent (by vol.) water and 2 percent (by vol.) surfactant. The initial breakup and atomization of a neat and emulsified fuel were quite similar at all conditions, and the evaporation rates appeared similar at various temperatures for pressures at or below about 300 kPa. At higher pressures with elevated temperatures the emulsified fuels of both types produce drops of significantly smaller Sauter mean diameter than the neat fuels as distance from the nozzle increases. These results are consistent with the microexplosion hypothesis, but there could also be alternative explanations. A detailed computer model which predicts heat up rates, steady state drop temperatures, evaporation rates, and drop trajectories has been used to help interpret the results. An additional point which has been observed is that the initial Sauter mean diameter produced with constant differential nozzle pressure is dependent on the air pressure with an exponent of about −0.4, i.e., SMD ∼ Pair−0.4. Some recent correlations often quoted omit the pressure (density) of air term.


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