Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa

Cassava (Manihot esculenta) is the most important staple food in sub-Saharan Africa. However, the shelf-life of the crop is short and, for this reason, the roots are usually processed into more stable products like cassava flour by village-based enterprises. Most of these enterprises use small-scale...

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Main Authors: Precoppe, M., Tran, T., Chapuis, Arnaud, Müller, Joachim, Abass, A.
Format: Journal Article
Language:Inglés
Published: Elsevier 2016
Subjects:
Online Access:https://hdl.handle.net/10568/78058
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author Precoppe, M.
Tran, T.
Chapuis, Arnaud
Müller, Joachim
Abass, A.
author_browse Abass, A.
Chapuis, Arnaud
Müller, Joachim
Precoppe, M.
Tran, T.
author_facet Precoppe, M.
Tran, T.
Chapuis, Arnaud
Müller, Joachim
Abass, A.
author_sort Precoppe, M.
collection Repository of Agricultural Research Outputs (CGSpace)
description Cassava (Manihot esculenta) is the most important staple food in sub-Saharan Africa. However, the shelf-life of the crop is short and, for this reason, the roots are usually processed into more stable products like cassava flour by village-based enterprises. Most of these enterprises use small-scale locally built pneumatic dryers, but such dryers still need further development, so the objective of this research was to improve their energy performance. Experiments were conducted at two cassava processing centres, one in Tanzania and one in Nigeria. Sensors were installed on the dryers, product samples were collected and the mass and energy balance of the equipment analysed, allowing the dryers' minimum air mass flow rates to be calculated. The air mass flow rates of both dryers were then reduced to a level approximating the minimum value. In Tanzania, the air mass flow rate of the dryer was reduced by 24%, while in Nigeria it was reduced by 14%. In both locations, the modifications decreased the dryers' heat input without jeopardising evaporation rates, and so not affecting the final moisture content of the dry products. Air temperatures at the dryer outlets decreased and relative humidity increased, while enthalpy remained unchanged. The energy required to evaporate 1 kg of water decreased by 20% in Tanzania and by 13% in Nigeria. The modification also improved energy efficiency by 25% in Tanzania and by 14% in Nigeria. However, in Nigeria, where yellow cassava flour was being used, the dryer modifications resulted in greater product colour losses.
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spelling CGSpace780582025-01-27T15:00:52Z Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa Precoppe, M. Tran, T. Chapuis, Arnaud Müller, Joachim Abass, A. cassava dryers energy efficiency heat input specific energy consumption minimum air flow rate Cassava (Manihot esculenta) is the most important staple food in sub-Saharan Africa. However, the shelf-life of the crop is short and, for this reason, the roots are usually processed into more stable products like cassava flour by village-based enterprises. Most of these enterprises use small-scale locally built pneumatic dryers, but such dryers still need further development, so the objective of this research was to improve their energy performance. Experiments were conducted at two cassava processing centres, one in Tanzania and one in Nigeria. Sensors were installed on the dryers, product samples were collected and the mass and energy balance of the equipment analysed, allowing the dryers' minimum air mass flow rates to be calculated. The air mass flow rates of both dryers were then reduced to a level approximating the minimum value. In Tanzania, the air mass flow rate of the dryer was reduced by 24%, while in Nigeria it was reduced by 14%. In both locations, the modifications decreased the dryers' heat input without jeopardising evaporation rates, and so not affecting the final moisture content of the dry products. Air temperatures at the dryer outlets decreased and relative humidity increased, while enthalpy remained unchanged. The energy required to evaporate 1 kg of water decreased by 20% in Tanzania and by 13% in Nigeria. The modification also improved energy efficiency by 25% in Tanzania and by 14% in Nigeria. However, in Nigeria, where yellow cassava flour was being used, the dryer modifications resulted in greater product colour losses. 2016-11-17 2016-11-29T08:51:01Z 2016-11-29T08:51:01Z Journal Article https://hdl.handle.net/10568/78058 en Limited Access Elsevier Precoppe, M., Tran, T., Chapuis, A., Müller, J. & Abass, A. (2016). Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa. Biosystems Engineering, 151, 510-519.
spellingShingle cassava
dryers
energy efficiency
heat input
specific energy consumption
minimum air flow rate
Precoppe, M.
Tran, T.
Chapuis, Arnaud
Müller, Joachim
Abass, A.
Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa
title Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa
title_full Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa
title_fullStr Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa
title_full_unstemmed Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa
title_short Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa
title_sort improved energy performance of small scale pneumatic dryers used for processing cassava in africa
topic cassava
dryers
energy efficiency
heat input
specific energy consumption
minimum air flow rate
url https://hdl.handle.net/10568/78058
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AT mullerjoachim improvedenergyperformanceofsmallscalepneumaticdryersusedforprocessingcassavainafrica
AT abassa improvedenergyperformanceofsmallscalepneumaticdryersusedforprocessingcassavainafrica