Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production

One of the most promising sources of biofuel is microalgae. Microalgae are unicellular photosynthetic organisms that have a high photosynthetic efficiency (10 to 20%) compared to other plant species (0.5%) (Huntley, et al., 2007). However, the large initial moisture content of microalgae (80 to 90%,...

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Main Author: Lopez, Neil Stephen A.
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Language:English
Published: Animo Repository 2011
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Online Access:https://animorepository.dlsu.edu.ph/etd_masteral/4087
https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10925/viewcontent/CDTG005071_P.pdf
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spelling oai:animorepository.dlsu.edu.ph:etd_masteral-109252023-01-16T00:17:02Z Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production Lopez, Neil Stephen A. One of the most promising sources of biofuel is microalgae. Microalgae are unicellular photosynthetic organisms that have a high photosynthetic efficiency (10 to 20%) compared to other plant species (0.5%) (Huntley, et al., 2007). However, the large initial moisture content of microalgae (80 to 90%, wet-basis) causes problems during oil extraction. According to Halim, et al. (2011), the lipid yield of dried microalgae is 33% higher than wet microalgae using hexane extraction. The study aims to predict the drying performance of microalgae biomass as a function of solar dryer design. The best combination of direct radiation, convective heat input and air flow rate was determined. A computational model for predicting the drying air temperature and relative humidity was solved using a spreadsheet program. The results of both models were validated by means of actual experimentation with a fabricated solar dryer and ANSYS Computational Fluid Dynamics simulation. Statistical analysis of the results showed that direct radiation (Qr) is more efficient than the convective heat input in increasing the drying rate. Qr allows the biomass surface temperature to get over the drying airs wet bulb temperature, giving rise to a significant increase in the drying rate. High air velocity results to inefficient drying. The computational model predicted the temperature and relative humidity of the drying air with an error percentage of 4.3% and 11.8%, respectively. ANSYS-CFD simulation was congruent with the assumptions used in the computational model. The regression equation generated from the characterization experiment was able to predict the average drying rate with an error percentage of 10%. The computational model was able to predict the temperatures and relative humidity of the drying chamber with an error percentage of 4.3% and 11.8%, respectively. Overall, the results show that drying rate is maximum at low air flow rate, high direct radiation and high convective heat input. Also, based on the measured available energy inside the solar dryer from actual experimentations, a microalgae dry mass yield of 800g/m2-hr which will be able to produce 180mL of oil per hour on a good sunny day was computed. 2011-12-02T08:00:00Z text application/pdf https://animorepository.dlsu.edu.ph/etd_masteral/4087 https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10925/viewcontent/CDTG005071_P.pdf Master's Theses English Animo Repository Biomass energy Microalgae Mechanical Engineering
institution De La Salle University
building De La Salle University Library
continent Asia
country Philippines
Philippines
content_provider De La Salle University Library
collection DLSU Institutional Repository
language English
topic Biomass energy
Microalgae
Mechanical Engineering
spellingShingle Biomass energy
Microalgae
Mechanical Engineering
Lopez, Neil Stephen A.
Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production
description One of the most promising sources of biofuel is microalgae. Microalgae are unicellular photosynthetic organisms that have a high photosynthetic efficiency (10 to 20%) compared to other plant species (0.5%) (Huntley, et al., 2007). However, the large initial moisture content of microalgae (80 to 90%, wet-basis) causes problems during oil extraction. According to Halim, et al. (2011), the lipid yield of dried microalgae is 33% higher than wet microalgae using hexane extraction. The study aims to predict the drying performance of microalgae biomass as a function of solar dryer design. The best combination of direct radiation, convective heat input and air flow rate was determined. A computational model for predicting the drying air temperature and relative humidity was solved using a spreadsheet program. The results of both models were validated by means of actual experimentation with a fabricated solar dryer and ANSYS Computational Fluid Dynamics simulation. Statistical analysis of the results showed that direct radiation (Qr) is more efficient than the convective heat input in increasing the drying rate. Qr allows the biomass surface temperature to get over the drying airs wet bulb temperature, giving rise to a significant increase in the drying rate. High air velocity results to inefficient drying. The computational model predicted the temperature and relative humidity of the drying air with an error percentage of 4.3% and 11.8%, respectively. ANSYS-CFD simulation was congruent with the assumptions used in the computational model. The regression equation generated from the characterization experiment was able to predict the average drying rate with an error percentage of 10%. The computational model was able to predict the temperatures and relative humidity of the drying chamber with an error percentage of 4.3% and 11.8%, respectively. Overall, the results show that drying rate is maximum at low air flow rate, high direct radiation and high convective heat input. Also, based on the measured available energy inside the solar dryer from actual experimentations, a microalgae dry mass yield of 800g/m2-hr which will be able to produce 180mL of oil per hour on a good sunny day was computed.
format text
author Lopez, Neil Stephen A.
author_facet Lopez, Neil Stephen A.
author_sort Lopez, Neil Stephen A.
title Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production
title_short Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production
title_full Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production
title_fullStr Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production
title_full_unstemmed Energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production
title_sort energy modeling, fabrication and evaluation of a small-scale natural convection solar dryer for microalgae biofuel production
publisher Animo Repository
publishDate 2011
url https://animorepository.dlsu.edu.ph/etd_masteral/4087
https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10925/viewcontent/CDTG005071_P.pdf
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