Nombre: RONILZA NASCIMENTO
Tipo: MSc dissertation
Fecha de publicación: 28/03/2018
Supervisor:
Nombre |
Rol |
|---|---|
| PAULO SÉRGIO DA SILVA PORTO | Advisor * |
| RODRIGO RANDOW DE FREITAS | Co-advisor * |
Junta de examinadores:
| Nombre |
Rol |
|---|---|
| TAISA SHIMOSAKAI DE LIRA | Internal Examiner * |
Páginas
Resumen: Microalgae stand out as one of the most promising raw materials for biofuel production because of its potential to accumulate lipid in its cells and also to capture atmospheric CO2. However, microalgae cultivation still demands a high cost due to factors such as nutrient expenditure, which are supplied to microalgae for their growth, energy expenditure on aeration and artificial lighting for crops. In this context, the research aims to improve the production process in the cultivation of the microalga Nannochloropsis oculata, reducing energy and nutrient expenses. For this, two experimental conditions were studied: in the first one, the aeration time was analyzed, with 6, 4 and 2 h aeration pumps shutdown and sodium silicate nutrient reduction at 60, 50 and 40 gL -1, with constant illumination; in the second condition, different photoperiods were analyzed from 24_h light: 00_h dark, 24_h light: 24_h dark, 12_h light: 12_h dark with aeration and constant nutrients. For experimental design of the first condition, we used a 32 factorial experiment, plus two central points, resulting in eleven experiments. In the second condition, the results were submitted to analysis of variance, for the significant differences, the Tukey test was applied. The best results achieved in the first condition were: cell maximum density 132 x 104 cel.mL-1, growth rate 0,17 day.1, specific growth rate 0.45 day-1, yield of the bio oil of 15, 11% and energy expenditure 50,40 kWh / g oil. In the second condition, the growth parameters that achieved the best results, when compared to the control variable (treatment 01), were values of maximum cell density of 115 x 104 cel.mL-1, specific growth rate 0,43 day-1, growth rate 0,17 day-1, bio-oil yield of 14,44% and energy expenditure 45,59 kWh / g oil. It was concluded that the microalgae cultures in both experimental conditions are satisfactory, allowing to reduce energy and nutrient expenses, since the values of verified bio-oil yields were close to values mentioned in the literature.
Keyword: Microalgae. Biodiesel. Nutrients. Aeration. Photoperiod. Energy
