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Construction guide of a small-scale pneumatic dryer to process cassava

Construction guide of a small-scale pneumatic dryer to process cassava

Precoppe, Marcelo ORCID: 0000-0002-7937-5782 (2020) Construction guide of a small-scale pneumatic dryer to process cassava. [Working Paper]

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To process cassava into flour, the roots are peeled, grated, pressed, pulverized, dried, and milled. For drying, the best choice of equipment is a pneumatic dryer, also known as flash dryer. Pneumatic dryers have low capital and operating costs, and they are easy to build and are simple to operate. Large-scale pneumatic dryers for cassava processing are nowadays efficient because it has been subject to development for a long time. In contrast, small-scale ones, of a size suitable for small-size enterprises, are in the early stages of development, and most commercially available ones, are incorrectly dimensioned. Pneumatic dryers are a continuously operated type of dryer, where wet solids are constantly loaded, and dried solids are constantly unloaded. In pneumatic dryers, drying occurs at the drying duct, while the solids are being transported pneumatically. Pneumatic dryers are classified as a convective dryer, however, in this dryer, hot air is not only used to remove moisture, but also to transport the material. In convective dryers in general, the energy performance is dictated by the heat transfer between solid and the hot air, the better the contact between them, the better the energy performance. In pneumatic dryers in specific, because the material is suspended in the air, the solid–hot air contact is total, and thus the heat transfer is optimum, explaining its high energy efficiency. However, pneumatic dryers must be properly dimensioned to operate efficiently. Windwood Millers Ltd. ( is a small-size cassava processing enterprise located in Lira, Northern region of Uganda. It is an established business supplying 400 tonnes of cassava flour, on an annual basis, to the domestic biscuit and brewery industries. Windwood Millers uses firewood powered pneumatic dryer to dry cassava, but their dryer was not correctly dimensioned, and consequently, its energy efficiency is very low. The objective of this working paper is to provide the instructions for Windwood Miller to build a properly dimensioned, and thus highly efficient pneumatic dryer.

Item Type: Working Paper
Additional Information: Precoppe, M. Construction guide of a small-scale pneumatic dryer to process cassava. CGIAR Research Program on Roots, Tubers and Bananas (RTB). RTB Working Paper. Available online at
Uncontrolled Keywords: pneumatic dryer
Subjects: S Agriculture > S Agriculture (General)
T Technology > TJ Mechanical engineering and machinery
Faculty / School / Research Centre / Research Group: Faculty of Engineering & Science
Faculty of Engineering & Science > Natural Resources Institute
Faculty of Engineering & Science > Natural Resources Institute > Food & Markets Department
Related URLs:
Last Modified: 08 Feb 2022 13:33

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