Product microwave drying

Aluminum, boron, calcium, iron, magnesium. Fruits, fruit products Microwave drying, wet ashing... 

Esveld, E., Chemat, F. and van Haveren, J., Pilot scale continuous microwave dry-media reactor, Part II application to waxy esters production, Chem. Eng. Technol., 2000, 23, 429. 

The extent of microwave drying can be correlated to the amount of power absorbed by the product, which is described by Eq. (44) ... 

If conduction or radiation is the predominant mode of heat transfer, the surface (and possibly the interior) moisture may literally boil regardless of the temperature or the humidity of the environment. This may be readily demonstrated by microwave drying. Thus, if control of granulation temperature is important, direct heat (convection) dryers usually offer greater control and product safety since the material s surface does not exceed the wet-bulb temperature during the steady state period. However, it will be shown later in this chapter that properly controlled dielectric drying may also be used to dry heat sensitive materials. 

Product cannot be produced by any other way. Again, the careful control of temperature combined with the unique manner in which microwave and dielectric energy couple into materials allows the drying of extremely thermolabile materials with no damage to the product. Occasionally, a unique beneficial effect may be obtained, such as the slight puffing of the pasta noodles when they are microwave dried. This allows them to be cooked more quickly. 

Capital equipment costs refer to the cost of the equipment and are sometimes a bit difficult to define. For example, a microwave drying system may increase the throughput of a product dramatically and thereby necessitate the purchase of additional packaging equipment, conveyors, feed systems, and the like. In that case, the overall capital outlay would be much higher than for the microwave dryer alone. 

In microwave drying, the product is exposed to very high-frequency electromagnetic waves. The transfer of these waves to the product is similar to the transfer of radiant heat. 

Microwave drying was combined with spouted bed fluidization technique (MWSB) for the drying of frozen blueberries [42]. MWSB drying was characterized by a substantial reduction in drying time and an improved product quality compared to freeze-, tray-, and SB-dried samples. 

Petrucci VE, Clary CD. Vacuum microwave drying of food products. Report No. 2897-3. California State University at Fresno, 1989. 

---