Spray drying process

A variation of the n on regen erabi e absorption is the spray dry process. Time slurry is sprayed through an atomizing nozzle into a tower where it countercurtendy contacts the flue gas. The sulfur dioxide is absorbed and water in the slurry evaporated as calcium sulfite-sulfate collects as a powder at the bottom of the tower. The process requires less capital investment, but is less efficient than regular scmbbing operations. 

It was observed that this technique was able to produce microparticles with a mean diameter of approximately 10.17 + 3.02 pm in a reasonable to satisfactory yield depending on the formulation. This value was observed to be higher for the polymer weight ratio of 1 3 (87.00 + 4.25 %), which indicates that ESIOO improves the final result of the spray-drying process. According to the SEM analysis, the polymeric microparticles were shown to be quite similar in shape. Regardless of the formulation, they appeared to be mostly concave and asymmetric (Figure 12). 

Water-Soluble Powders Obtained by Drying (Freeze AND Spray Drying) Processes... 

First attempts to incorporate pre-formed magnetite colloids within alginate/silica nanocomposites via a spray-drying process have been described, but formation of lepidocrocite y-FeOOH and fayalite Fe2Si04 was observed, attributed to Fe2+ release during the aerosol thermal treatment [53],... 

For example, amorphous clarithromycin was prepared by grind and spray-drying processes, and XRPD was used to follow changes in crystallinity upon exposure to elevated temperature and relative humidity [59]. Exposure of either substance to a 40°C/82% RH environment for seven days led to the formation of the crystalline form, but the spray-dried material yielded more crystalline product than did the ground material. This finding, when supported with thermal analysis studies, led to the conclusion that the amorphous substances produced by the different processing methods were not equivalent. 

Figure 1.2. Schematic of spray drying process open-cycle co-current layout.

In addition to the designs mentioned above, other atomizer configurations such as those used in spray combustion and spray drying processes may also be considered as an alternative in gas atomization of melts for special purposes after appropriate modifications. 

The spray drying process can be thought of as a method of preserving in the solid state the equilibrium between the two forms of dextrose which prevails in solution. The composition of the solid does not agree strictly with that of the solution, undoubtedly because some fractional crystallization takes place before all of the water has been removed from the solid. 

However, in some cases scale-up involves a radical re-design of the original process to ensure it can be successfully transferred. For instance, when transferring spray drying processes from Buchi-type equipment to GEA Niro-type equipment there is limited transferrable knowledge that can be applied as the operating conditions are very different. 

Figure 7.23 Schematic diagram of spray drying process for the formation of calcined magnesium zinc ferrite. From J. S. Reed, Principles of Ceramics Processing, 2nd ed. Copyright 1995 by John Wiley and Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

The focus of this work was to determine if a glyco-peptide or a simple dextrinized, oxidized starch could be produced which would enhance the behavior of a starch-based polymer for spray dried flavoring production. Enhancement of a starch s lipophilic/hydrophilic balance was anticipated to maintain the polymer s film forming" and cohesive wall development during the spray drying process while improving its emulsifying/interfacial activity capabilities. 

The data show that when spray-drying a 30% lemon oil level on the weight of the carrier, the starch octenylsuccinate only loses O.37o of the oil during the spray-drying process. Surface flavor oil was also lower for the starch octenylsuccinates which indicates excellent encapsulation efficiencies. 

Spray-drying costs are always a factor in determining the economics of an encapsulated product. Drying costs are related to the amount of water that must be removed in the spray-drying process. It is therefore advantageous to enter the drier at the highest possible solids that still gives... 

Phenolic antioxidants together in combination with thiodiprop-ionate compounds as synergists have been used for this purpose, e.g., n-octadecyl-3-(4 -hydroxy-3, 5 -di-ferf-butylphenyl)propionate and dilauryl thiodipropionate (14). These systems have a tendency to develop colored impurities as a byproduct of their antioxidant function. The production of colored impurities becomes particularly evident in spray drying processes that utilize partially inert atmospheres (12). 

Oomah, B.D. and Mazza, G. 2001. Optimization of a spray drying process for flaxseed gum. Inti. J. Food Sci. Technol. 36, 135—143. 

Chang, S. G. "Spray Drying Process for Simultaneous Removal of S02 N0X, and Particulates from Flue Gas", LBL case no. IB-643, U.S. patent pending, 1986. 

Microcrystalline cellulose is the most compressible of any direct compression excipient. Producing a tablet of a given hardness requires less compression force for other materials. Therefore, it is usually mixed with another filler to achieve ideal compactibility and flowability of a direct compression formulation. Large particle size grades of microcrystalline cellulose are made by spray-dried processes to form dry and porous particle surfaces. The porous surfaces provide adsorption sites needed for fine dmg particles in low-dose formulations. However, microcrystalline cellulose contains trace amounts of peroxides that may lead to chemical incompatibility with oxidatively sensitive dmg substances.34... 

In a spray drying process, the determining dimension is the particle diameter, dp. With dp = 0.1 mm and assuming conditions usually prevailing in spray dryers, Sh = 70. Therefore, this process will be diffusion-limited, that is internally governed. 

Labeling Indicate whether it is anhydrous or the monohydrate or a mixture of both forms if it has been prepared by a spray-drying process. 

The spray drying process described below has many appealing features for the... 

As far as the dimensions of the chambers are concerned, they are imposed by the hydrodynamics of the drying process as illustrated in Figure 3.12. It is seen that in order to achieve the particle size (around 70 pm) of interest in FCC catalysts, the drying chamber diameter is between 3-4 meters. Such dimensions make the spray drying process difficult to downscale for a detailed study and modeling of this unit operation. 

Bruckner M, Bade M, Kunz B (2007) Investigations into the stabilization of a volatile aroma compound using a combined emulsification and spray drying process. Eur Food Res Tech 226 137-146... 

Powders intended for nasal administration have to be optimized in terms of particle size and morphology as these properties are related to potential irritation in the nasal cavity [23], Certain procedures (e.g., spray drying process) can modify the particle size of the drug powder raw material, but in order to optimize the morphology and flowability properties of some pure drug powders, excipients need to be used. Sacchetti et al. [28] reported that the use of mannitol as a filler and hydroxy-propylmethyl cellulose (HPMC) as a shaper of spray-dried caffeine microparticles modified the typical needle shape of spray-dried caffeine to a more convenient roundish shape. Further addition of polyethylene glycol (PEG) resulted in increased... 

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