Spray drying pumping

Reaction times can be as short as 10 minutes in a continuous flow reactor (1). In a typical batch cycle, the slurry is heated to the reaction temperature and held for up to 24 hours, although hold times can be less than an hour for many processes. After reaction is complete, the material is cooled, either by batch cooling or by pumping the product slurry through a double-pipe heat exchanger. Once the temperature is reduced below approximately 100°C, the slurry can be released through a pressure letdown system to ambient pressure. The product is then recovered by filtration (qv). A series of wash steps may be required to remove any salts that are formed as by-products. The clean filter cake is then dried in a tray or tunnel dryer or reslurried with water and spray dried. 

Encapsulated Flavors. Modified procedures during the past decade have permitted the preparation of encapsulated flavors with flavor levels over twice that of prior available products. Spray drying has been the principal key to this success. First, an oil flavnr is emulsified into an aqueous solution or is dispersed in an edible carrier material, after which the emulsion is pumped through an atomizer into a high-temperature chamber. The water evaporates rapidly, and particles of carrier material are formed around the flavor. However, some of the flavor component reaches the surface of the product. This requires the addition uf antioxidants to suppress oxidative changes in the flavor ingredient. 

The recovery of whole cells is best explained by the manufacturing procedure for baker s yeast. This process is almost identical to the early stage of protein recovery, except that the final product is the cell instead of the filtrate. After fermentation, the cells are spun out with a centrifuge, washed with water, and recentrifuged to yield a yeast cream with a solids concentration of approximately 18 percent. Cream yeast can be loaded directly into tanker trucks and delivered to customers equipped with an appropriate cream yeast handling system. Alternatively, the yeast cream can be pumped to a plate and frame filter press or an RDVF and dewatered to a cakelike consistency with 30-32 percent yeast solids content. The press cake yeast is crumbled into pieces and packed or spray-dried for dry products. After packaging, the yeast is ready for shipping to retail. 

The multipurpose high pressure pilot unit in picture 4 is built for HP-Spray Drying, HP-Micronization and for SFE of solid products. As can be seen on the corresponding flow sheet (figure 2), the C02 circulation system and the separation module are exactly the same as in the multipurpose SFE unit. However, the column and the product pump had to be adapted to the requirements of the "new" application. 

Before the 1950s, soap was manufactured in the saponification process. Soap was prepared in large kettles in which fats, oils, and caustic soda were mixed and heated. After cooling, salt was added to the mixture forming two layers soap and water. The soap was pumped from the top layer to a closed mixing tank where builders, perfumes, and other ingredients were added. Finally, the soap was rolled into flakes, cast, or milled into bars, or spray-dried into soap powder [1, 2]. 

The spray drying process is conceptually simple a solution is pumped through an atomizer, a plume of liquid droplets containing solid components is created and subsequently exposed to a suitable gas stream to promote rapid evaporative mass transfer of the liquid carrier into the gas. When sufficient liquid mass has been transformed to vapor, the remaining solid material in the droplet forms an individual dried particle which is then separated from the gas stream. 

Wheels with radial vanes have one important drawback, i.e., their capacity for pumping large amounts of air through the wheel. This so-called air pumping effect causes unwanted product aeration, resulting in powders of low bulk density for some sensitive spray dried products. 

A subcutaneously implantable protein delivery system made up of a DUROS osmotic pump containing dry (lyophilized or spray-dried) protein formulations in nonaqueous suspending vehicle is being developed for long-term release of proteins at the target site. The duration of protein release can be... 

In order to consider spray drying, certain criteria about the material must be met. The feed slurry viscosity must be low enough whereby it can be pumped through either a rotary atomizer, a two fluid nozzle or a high... 

An alternative to spray drying of solids that are suspended in a liquid using high pressure single and two phase or rotary nozzles (see Section 7.4.3) is the break-up of a low pressure stream of slurry in gas dynamic atomization. In this process, the fluid is pumped to an orifice where it is released into a pulsating flow of hot gas (Fig. 7.81) and atomized. 

Process selection around a core material is dependent upon core material properties such as thermal stability, viscosity if it is a liquid, particle size and shape if it is a solid, density, reactivity, and solubility. Processes such as spray chilling or spray coating can expose core materials to elevated temperatures for longer periods of time, compared to spray drying, as the mixture remains heated as it awaits pumping to an atomization nozzle. Other processes, such as coextrusion or some emulsion processes, can be carried out at or below room temperature. For example, ionic gelation coupled with coextrusion can be used to encapsulate oils or biological materials at or below room temperature." Processes like solvent evaporation can be operated under vacuum to remove the matrix solvent rather than the use of temperature. ... 

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