Powdered detergents spray drying

The main atmospheric pollution problem in soap manufacturing is odor. Odors emanating from the spray dryer may be controlled by scrubbing with an acid solution. The production of soap powder by spray drying is the single largest source of dust in the manufacture of synthetic detergents. 

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. 

Fig. 7. Plant for spray-drying of detergents and soaps. 1, Burner 2, air combustion 3, cold air fan 4, hot air generator 5, spray-drying tower 6, cleaning ring 7, no22les circuit 8, tower suction cyclones group 9, tower suction fan 10, double-flap dischargers 11, recovery powder cyclone 12, recovery powder fan 13, belt conveyor 14, air lift 15, air lift suction cyclones 16, air lift suction fan 17, double-flip dischargers 18, vibrating sieve.

Spray drying 0.05 to 0.5 Low Morphology of spray dried powders can Instant foods, dyes, detergents, ceramics... 

The LAS/AS and LAS/AS/AES combinations used in some U.S. spray-dried laundry powders for more than 30 years have provided good detergency with moderate to high foaming performance [39]. A typical example of a low-density, spray-dried, high-foaming laundry powder is shown below ... 

In addition to detergency performance and feedstock economics, other factors related to the processing of these powder formulations must be considered, such as sulfonation/sulfation, crutcher slurry preparation, and spray drying. AS and AES are thermally and hydrolytically less stable than LAS. Care must be taken in spray drying to avoid decomposition and pluming problems. This may place a limitation on the levels of AS and AES in spray-dried laundry powders. 

The introduction of concentrated laundry detergent powders in Japan during 1986-1987 produced a substantial increase in the consumption of LAB in the subsequent 3-4 years as the market changed from low-density, spray-dried powders to the concentrated (compact) products. In these products, which may contain up to 40% surfactant, the cost/performance advantages of LAS are of significance. In addition, LAB sulfonic acid is well suited for the production of high-active, high-density (about 1.0 g/cm3) laundry powders by routes other... 

Spray-dried powders are formulated to give the best overall cleaning performance and flow characteristics at the lowest possible formulation costs. Typical spray-dried detergent formulations are shown in Table 36.6. Slurry preparation is considered to be the single most important factor in spray drying. Control of the raw material order of addition, slurry solids level, slurry temperature, viscosity, and aeration enable manufacturers to deliver the desired final product characteristics. The spray tower itself is simply a contained heat source that removes moisture at a uniform rate dependent upon the quality and the quantity of feed to the dryer. If feed variables are not controlled, variability in the... 

Fig. 6.3-1 Diagram of a spray-drying system for the production of conventional laundry detergent powder [B.60]...

Fig. 6.3-2 Flow diagram of a traditional spray drying process for the manufacture of laundry detergent powder [B.102]...

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