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Example 11 - Evaporation and Drying 2

Problem

This example is an extension of example 10. After the same liquid material is concentrated it needs to be dried firstly in a spray dryer and then in a vibrated fluid bed dryer. The evaporation and first stage drying process has already been described in the example 10. The drying air of the spray dryer needs to be at 103.2 kPa and 140 ^oC. The exhaust air is at 68 ^oC. Material outlet from the spray dryer is at 55 ^oC and 0.08 kg/kg (wet basis) moisture content. The drying air of the vibrated fluid bed dryer needs to be at 103.2 kPa and 85^oC. The exhaust air is at 55 ^oC. Material outlet from the spray dryer is at 52 ^oC and 0.03 kg/kg (wet basis) moisture content.

Solution:

The flowsheet is constructed as in Figure 10a. As is seen in this flowsheet part of the secondary vapor from the second effect evaporator is used to preheat the drying air.

Figure 11a

The results are displayed in Figure 11b

Figure 11b