Powdered detergents drying

Fig. 6.12 Microscopic image of spray-dried powder (detergent, drying temperature 200°C) (Rabaeva and Zbicinski, 2010). (a) Non-foamed (b) Foamed.

Air blast fluidisation Air blast lifts and mixes particles Dry powders and granules Milk powder detergents, chemicals... 

Use Household dry bleaches, dishwashing compounds, scouring powders, detergent sanitizers replacement for calcium hypochlorite agriculture. 

And all over the place Printed circuit laminates Audio and video tapes Adhesives Antifreeze Telephone poles Roadmarkers and paints Fishing nets, ropes, and string Fish and vegetable boxes Horticultural him Powder and liquid detergents Dry cleaning huids Disposable syringes Contact lenses... 

To produce conventional laundry detergent powder, spray drying is the established method (the tower process). Fig. 6.3-1 shows the block diagram of such a system [B.60]. 

Products and Uses A component in dry bleaches, dishwashing detergents, scouring powder, detergent sanitizers, and pool disinfectants. Used as a replacement for calcium hypochlorite and bleaching materials. 

Products and Uses Frequently found in household dry bleaches, dishwashing compounds, scouring powders, detergent sanitizers, laundry bleaches, swimming pool, hot tub, and Jacuzzi disinfectants. Used as a bactericide, algicide, bleach, and deodorant. 

Spray drying is used to dry pharmaceutical fine chani-cals, foods, dairy products, blood plasma, numerous organic and inorganic chemicals, rubber latex, ceramic powders, detergents, and other products. Some of the spray-dried products are listed in Table 9.1, which also includes typical inlet and outlet moisture content and tanperatures together with the atomizer type and spray dryer layout used. 

The detergent drying process is a large-scale process, and in modem installations digital control systems are used to control the plant. However, the control of product properties such as density and blown powder moisture tends not to be fully automated, partly due to the multivariable uature of the product properties and lack of robust measurement systems. Therefore, there tends to be a human operator responsible for the starting-up, center lining, and shutting down of the process. 

Foam stabilizers, their solid form is conducive to non tacky spray dried powdered detergent formulations. Excellent foam boosters at elevated temperatures. 

A biodetergent is usually just a normal detergent which contains enzymes. However, enzymes are not thermostable and cannot be e msed to the high temperatures and humidities encountered in the powder detergent production process. Therefore, they are postadded to the spray-dried powder with other heat-sensitive ingredients, such as perfumes, bleaching... 

Specialty surfactants are mostly secondary surfactants, not the primary ingredient in a formulation, and gamer somewhat higher prices in the marketplace. Normally, over time a surfactant once considered a specialty slowly becomes a commodity. However, some surfactant classes can have both coimnodity and specialty uses. In fact, it is sometimes possible to convert a coimnodity into a specialty. For instance, linear alkylbenzene sulfonate (LAS) is considered a commodity. As such, it is sold either in the acid form at 96% active or as the sodium salt at 40% to 60% active. There are many producers of and applications for LAS. As a specialty, the sodium salt is sold as flakes at 90% active. Few producers and few applications need this material, but it commands a higher price. One main use is for dry blending in powdered detergents for smaller manufacturers, where it makes it possible to avoid purchase of expensive spray-drying equipment. Here the special property is its physical form. 

Phospha.tes, Pentasodium triphosphate [7758-29-4] sodium tripolyphosphate, STPP, Na P O Q, is the most widely used and most effective builder in heavy-duty fabric washing compositions (see also Phosphoric acid and phosphates). It is a strong sequestrant for calcium and magnesium, with a p c of ca 6, and provides exceUent suspending action for soils. Because of its high sequestration power, it also finds extensive appHcation in automatic-dishwashing detergents. Sodium tripolyphosphate forms stable hydrates and thus aids in the manufacture of crisp spray-dried laundry powders. 

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