Design, fabrication and preliminary testing of a horizontal flat- plate photobioreactor for the outdoor cultivation of chlorella vulgaris

Date

2011

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Adviser/Committee Chair

Rex B. Demafelis

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Abstract

A horizontal flat plate photobioreactor fo the outdoor cultivation of Chlorella vulgaris was designed and fabricated. The photobioreactor dimensions are 1mx0.85mx0.15m and it has a working volume of 100L. Air was supplied by installing air stones at the bottom of the photobioreactor: a Vespa SF 20IP compressor was used to aerate the Chlorella vulgaris culture. A paddle wheel was also installed in the photobioreactor to direct the flow of the culture and for better mixing. Plastic tubes were attached at the top cover of the photobioreactor to serve as degassers. Four sampling ports were located at the side of the photobioreactor. Two trial runs were performed on the cultivation of Chlorella vulgaris. The maximum optical density achieved for the ₁ˢᵗ trial was .52325 (425nm) and 0.46975 (625nm) while for the 2ⁿᵈ trial was 1.0035 (425nm) and 0.62875 (625nm). The use of net as shade for trial 2 has been favorable since light intensity from the sun was very high. The ₁ˢᵗ and 2ⁿᵈ trials have a specific growth rate of 0.119 day⁻¹ and a doubling time of 5.824766 days:; the residence times was 8.4033 days. For the continuous operation, the computed feed and output flow rate was 8.263889 mL/min. After the first residence time , which is 8,4033 days, the continuous experiment was operated in a different basis. The residence time considered is twice the computed residence time which is 16.8066 days: the new feed flow rate was 4.131975 mL.min. A decrease in the reading of the optical density is observed in the graph. This may be accounted to lack of feed substrate that can sustain the nutrient requirements of the concentrated algae inside the reactor . Monitoring of the amount of residual nutrients during the continuous of Chlorella vulgaris was also done.Chlorella vulgaris neither a large increase nor decrease in nutrient consumption of the microalgae that is significant enough to increase or decrease the biomass concentrations. The phosphorous in the media was almost consumed, there is a significant amount of nitrogen left which ranges from 3-8mg/L; thus the nitrogen can therefore be concluded as not a limiting nutrient.

Language

English

LC Subject

Biofuel, Nuclear reactors--Testing

Location

UPLB College of Engineering and Agro-Industrial Technology (CEAT)

Call Number

LG 993 2011 E62 B36

Document Type

Thesis

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