Analysis of Failure Modes Effect and Criticality Analysis (FMECA): A Stand-Alone Photovoltaic System
Omar Ngala Sarr,
Fabe Idrissa Barro,
Oumar Absatou Niasse,
Fatou Dia,
Nacir Mbengue,
Bassirou Ba,
Cheikh Sene
Issue:
Volume 5, Issue 2, April 2017
Pages:
40-47
Received:
24 February 2017
Accepted:
8 March 2017
Published:
27 March 2017
Abstract: This study deals with the implementation of a methodological guide for the maintenance of photovoltaic systems in Senegal. Typical PV systems components are photovoltaic panels, and inverter, a regulator, connecting cables and the battery; so Failure Modes Effect and Criticality Analysis (FMECA) is performed on the PV system in order to increase the reliability and reduce system failures. To do that, a functional analysis of the system through an octopus diagram and a dysfunctional analysis through a fault tree, are used as a decision support for the choice of the coefficients to obtain the full system FMEA. The obtained results allowed us to detect about 40% of the types of failure that cause over 60% of system malfunction. Anticipating these types of failure through preventive maintenance would make the PV system more reliable.
Abstract: This study deals with the implementation of a methodological guide for the maintenance of photovoltaic systems in Senegal. Typical PV systems components are photovoltaic panels, and inverter, a regulator, connecting cables and the battery; so Failure Modes Effect and Criticality Analysis (FMECA) is performed on the PV system in order to increase th...
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Statistical Optimization of Lipid Extraction from Wastewater Scum Sludge and Saponifiable Lipids Composition Analysis
Issue:
Volume 5, Issue 2, April 2017
Pages:
48-57
Received:
31 March 2017
Accepted:
11 April 2017
Published:
18 October 2017
Abstract: In the present study, Design of Experiment (DoE) as a statistical method was adopted for optimizing conditions for lipid extraction from scum sludge. Four different extraction variables were investigated: methanol to hexane ratio (%), solvent to sludge ratio (ml/g), temperature (°C), and extraction time (h). During the optimization process, saponifiable lipids (SLs) content of the extracted lipid was analyzed. Screening experiments revealed that methanol to hexane ratio (X1), solvents to sludge ratio (X2) and temperature (X3) showed a significant effect on Ylipid (p < 0.05). Lower methanol to hexane ratio and higher solvent to sludge ratio showed the highest positive effect on lipid yield (Ylipid). No significant effect on extraction time on Ylipid was observed. The positive relationship between lower methanol to hexane ratio and the amount of lipid extracted can be attributed to the presence of higher amounts of neutral lipids in scum sludge. According to Box-Behnken design and Response surface method (RSM), the maximum lipid extraction yield (Ylipid) predicted through numerical optimized conditions by the model for highest desirability (0.995) was 29.614% at methanol to hexane ratio (%) of 42%, solvent to sludge ratio (v/wt) of 51 ml/g, temperature at 87°C for extraction time of 6 hours. The FAMEs yield produced from ex-situ acid-catalyzed esterification/transesterification of the methanol-hexane co-solvent extracted lipid ranged between 7.9-9.3% (wt/wt) based on sludge weight. Fatty acid profile of FAMEs was found to be was found to be dominated by Oleic acid methyl ester (C18: 1) followed by methyl Palmitate (C16: 1) representing 39.4% and 24.3% of FAMEs composition respectively. The correlation analysis of extraction variables and FEMAs yield revealed that solvent to sludge ratio (ml/g) has the highest positive significant correlation with FAMEs yield (p-value < 0.05). However, methanol to hexane ratio (X1) and temperature (X3) were inversely correlated with FAMEs yield.
Abstract: In the present study, Design of Experiment (DoE) as a statistical method was adopted for optimizing conditions for lipid extraction from scum sludge. Four different extraction variables were investigated: methanol to hexane ratio (%), solvent to sludge ratio (ml/g), temperature (°C), and extraction time (h). During the optimization process, saponif...
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