Document Type

Thesis - Open Access

Award Date

2017

Degree Name

Master of Science (MS)

Department

Agricultural and Biosystems Engineering

First Advisor

Gary A. Anderson

Keywords

Biofuels, Biomass, Cyanobacteria, Micro algae, Photobioreactor, Sparger

Abstract

This thesis presents the estimated value of materials required to grow 1g of biomass and the analysis of the light intensity with respect to flow path and flow rate. This thesis aims to design the sparger for a flat plate Photobioreactor, study the flow patterns at different flow rate of air flow and check the performance of flat plate PBR by growing the cyanobacteria. The estimated value to produce 1g of biomass (C44.6H7O25N7.68P0.9S0.3) was 0.099g of N, 0.493g of C, 0.160 g of Na, 0.026 g of P, 0.009 g of S, and 0.007 g of Mg. The energy required to fix carbon atoms in 1 mole of biomass was found to be 78,584,302 J. The net energy loss of the system was calculated by subtracting net enthalpy of reactants from net enthalpy of product which was found to be -3800.724 KJ. Light plays a great role in the performance of PBR. The equation was also developed to find the relationship of light intensity with path length and gas flow rate. The sparger plays a major role in deciding the performance of the PBR. It is one of the means for mixing so that the gas can pass though the growth medium by bubble which is created by the passing the gas through the holes of the sparger. Mixing helps in proper distribution of nutrients to the medium in Photobioreactor (PBR), maintaining the uniform temperature. The sparger was designed using a SPARGER software built on a Java platform to simulate the flow and pressure distribution along its length. Sparger diameter of 0.5 inch was designed with a hole diameter of 1/32 inch and spacing of 4.04 cm. The simulation result showed non-uniformity of less than 5% and the percentage of airremaining after the last hole less than 1%. With the designed sparger the flow patterns of bubbles were observed in 160L water in three different conditions. The first one was using the different number of sparger pipes ranging from 1 to 4. The second one is using the different gas flow rate and the third one is observing the flow patterns at different height. Larger number of sparger pipes shows the better mixing, 10LPM flow rate was observed to have a uniform bubble distribution and at the higher depth the flow was observed to be air lift. The designed sparger for the PBR system was used in a PBR to grow cyanobacteria. Cyanobacteria was grown on BG-11 media and the highest concentration of biomass was found on 13th day with a value of 928 mg/L. The physical parameters like Oxidation Reduction Potential (ORP), Dissolved Oxygen (DO), pH and temperature were studied. The range of ORP, DO, pH and temperature were found to be 169.76 to 327.67 mV, 8.68 to 8.20 mg/L, 6.15 to 8.09 and, 26.81°C to 30.91°C respectively. The observed results were compared to the small reactor results.

Library of Congress Subject Headings

Microalgae -- Growth.
Algal biofuels.
Photobioreactors.
Biomass energy.

Description

Includes bibliographical references (pages 87-103)

Format

application/pdf

Number of Pages

129

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

Share

COinS