The results and the experience gained in the design, manufacture and start-up of high-speed centrifugal driers, operating with a dynamic thin layer, together with specific knowledge of the saponification field, enabled VRV to extend their application successfully to continuous reactions and, specifically, to saponification reactions,using the same operation principles on which the machine is based.

The outcome is a multipurpose equipment, which, in a single step, can carry out three different process stages, at least:

• Mixing/reaction
• Drying
• Granulation/cooling.

The execution of the single-step high speed reactor takes full advantage of the excellent characteristics of mechanical reliability of the basic machine. This allowed to place the blades, with which the rotor is equipped, at the minimum possible distance from the inner surface of the stator.
This arrangement, together with the blades profile, the centrifugation elements and the operation high tip speed, allows to reach an effective and thorough mixing of the various raw materials and additives, helping their close contact and, consequently, the completion of the reaction in short times.
 The fluid and dynamic thin layer which forms by  the combined action of the various mixing and centrifugation elements is removed quickly and continuously from the inner wall of the stator, to avoid any product degradation and darkening due to long thermal exposure. The removing effect also helps to prevent the soiling of the exchange surface: if the stator  wall is kept clean, the coefficients of exchange and, therefore, the thermal flows settle on very high values, higher, anyway, than those obtainable in other more or less similar systems. Thanks to its configuration, the reactor can operate at differentiated temperatures according to the process reuirements. In the specific case of the saponification, that part of the machine where the reaction and the drying take place is heated (also at different temperatures) while the section where the granule forms is cooled.

RAW MATERIALS

• Any kind of fatty acids from different animal and vegetable fats and oils
• Distilled fatty acids
• Mixture of neutral fats and fatty acids
• Sodium hydroxide 30-32% solution in weight
• Normal or softened (20°F) process water
• Various additives

UTILITIES

• Saturated steam at 9 bar (179°C)
• Cooling water at 15°C
• Cooling water at 27°C
• Instrumentation air, pressure 7 bar, dew point -20°C
• Power 380 V (+/- 10%), 50 Hz, three-phase

EXAMPLES OF HOURLY PRODUCTION CAPACITY AND RAW MATERIALS CONSUMPTION

With a reactor type 13/60, having an internal total useful surface of 20 m2, several saponification reactions are possible, such as, for instance:

• with 1200 kg/h of tallow fatty acids, 1480 kg/h of soap at 80% of total fatty acids are obtained
• with 1000 kg/h of mixture composed of 90% of tallow fatty acids + 10% of lauric acid, 1240 kg/h of soap at 80% of total fatty acids are obtained
• with 720 kg/h of mixture composed of 70% of tallow + 20% of tallow fatty acids + 10% of lauric acid, 880 kg/h of soap at 80% of total fatty acids + 4-5% of glycerine are obtained
• with 600 kg/h of mixture composed of 90% of tallow + 10% of lauric acid, 680 kg/h of soap at 80% of total fatty acids + 5-6% of glycerine are obtained.

SPECIFIC CONSUMPTION PER TON OF PRODUCT
(Based on raw material as per first example hereabove)

• saturated steam                 400 kg
• cooling water at 27°C           21m³
• cooling water at 15°C            9m³
• power                                    50kW