MODELING SEQUESTRATION OF CARBON DIOXIDE EMISSIONS FROM FOSSIL FUEL POWER PLANTS BY ALGAE LAGOONS

摘要

Global warming from greenhouse gas emissions, particularly carbon dioxide (CO2), remains a serious environmental issue for our planet. Current trends indicate increasing use of fossil fuels, and increasing emissions of CO2. Power plants, which account for about 1/3rd of the total greenhouse gas emissions, represent an excellent opportunity to capture and sequester CO2 emissions. Routing power plant emissions through algal lagoons has been proposed as a promising cost-effective treatment. A model was developed to study these lagoons. The model used Stella, a graphically based modeling program with equations and operating parameters were obtained through the literature. Application of the model indicated an optimal operating temperature of 22oC. Also, nutrient levels of >0.78 g/m3 of phosphorus and of >1.1 g/m3 of nitrogen would provide maximum carbon removal. Lagoon size depended on the treatment goal and on the size of the plant, but could be substantial. Artificial heating from waste heat from the plant greatly increased algal biomass during the winter-time, and resulted in sizeable increases in carbon sequestration. Latitude was also an important operating parameter, as it is related to the available solar energy to the algae. Advances in the technology could yield more efficient lagoons and creative applications for the generated biomass could offset some of the costs of the system. However, it would likely take a dramatic change in the regulatory environment to implement use of greenhouse gas control technologies. Nevertheless, a pilot-scale application would provide very important data to refining design criteria for such lagoons.