Industrial nations in general and the United States of America in particular are facing an unprecedented combination of economic and environmental challenges. First, they face the formidable challenge to meet expanding energy needs without adding intolerable amounts of greenhouse gases to the atmosphere and further impacting climate and the environment. The reserves of cheap natural resources the world has been relying on for decades are now estimated in tens of years. Evidence of global warming already gathered around the globe and, most likely, due to industrial activities will put an additional stress on the fragile balance we have been enjoying. In order to face these formidable challenges and to create technological and economic opportunities, the United States should reduce its dependency on foreign fossil fuels and rely more on a combination of (i) sustainable energy conversion and transportation systems, (ii) oil-free energy sources, and (iii) new technologies for capturing and converting carbon dioxide.
The objective of this project is to perform a comprehensive study to simultaneously mitigate carbon dioxide and produce hydrogen. It offers a cheap, efficient, scalable, autonomous, and reliable system for producing hydrogen from microbial consumption of carbon dioxide and absorption of solar light.
Project Performed in Collaboration with Prof. Jenny Jay from Civil and Environmental Engineering at UCLA
Cyanobacteria produce hydrogen and oxygen by (i) consuming the CO 2 gas as their carbon source and (ii) absorbing solar light as their energy source.
Cyanobacteria Anabaena variabilis are:
n
. Filamentous, heterocystous cyanobacteria
n. Feature high hydrogen production capacity in the absence of nitrogen
n. Considered to be good carbon dioxide consumer
n. Approximately 5 mm in diameter and 100 mm long
. nTheir genome has been sequenced
We have designed and built, and now are operating a fully instrumented photobioreactor. The following measurements are systematically performed:-
Environment
In the liquid phase -
In the gas phase
Incident light intensity
gas in-flow rate
pressure
The photobioreactor is operated using two stages. Switching from Stage 1 to Stage 2 takes place when the nitrate concentrations in the liquid phase vanishes
Stage 1: Carbon Dioxide Consumption and Bacterial Growth
. presence of nitrates and nitrogen
. sparging with 95% air and 5% CO2 at 170 mL/min
. irradiance: 65-75 umol/m2/s
Stage 2: hydrogen Production
. absence of nitrates and nitrogen
. sparging with pure Argon at 45 mL/min
. irradiance: 150 umol/m2/s
The growth phase lasted 110 hours
The H2 production phase lasted more that a week
The light to hydrogen energy conversion efficiency reached 0.5%
The light to biomass energy conversion efficiency was 4.7%
- J. Yin and L. Pilon, 2006. Efficiency Factors and Radiation Characteristics of Spherical Scatterers in Absorbing Media. Journal of the Optical Society of America – A (in press).
- H. Randrianalisoa, D. Baillis, and L. Pilon, 2006. Improved Inverse Method for Determining Radiation Characteristics of Fused Quartz Containing Bubbles, Journal of Thermophysics and Heat Transfer (in press).
- H. Berberoglu, N. Barra, L. Pilon, and J. Jay, 2006. Photobiological Hydrogen Production and Carbon Dioxide Mitigation by Anabaena variabilis 29413-U , ASME International Mechanical Congress and Exposition, Chicago , IL , November 5-10, 2006 , IMECE2006-16144.
- H. Berberoglu, J. Yin, and L. Pilon, 2006. Simulating Light Transfer in a Bubble Sparged Photobioreactor for Simultaneous Hydrogen Fuel Production and CO 2 Mitigation , Eurotherm Seminar 78, Computational Thermal Radiation in Participating Media II. April 5–7, 2006 , Poitiers , France (Editions Lavoisier, Paris), pp. 297-306.