Capture CO₂ From Actual Flue Gas With Microalgae

Dioxide carbon emission reduction has become the hot filed of air pollution control research. At present, there are physical, chemical and biological methods to fix CO₂. Because of the various advantages of microalgae, such as high photosynthetic rate, fast propagation speed, strong environmental adaptability, high processing efficency, it is consided as the most promising CO₂ fixation technique.In this paper, dioxide carbon fixation was studied through the three fiels, developing a pilot system to fix CO₂ from actual industrial flue, investigating the improving function of growth regulator on the growth and CO₂ fixation rate of microalgae, and discovering the mechanism of glycine to improve the microalgal growth as a growth regulator. The main contents of this work are as follows:A pilot system is developed for fixing CO₂ from actual flue gas with the microal fixing CO₂ technique. The pilot system was built in Wuhan Iron and Steel (Group) Corporation. A well design 100 L air-lift photobioreactor was used. A UV-induction eveloved scenedesmus obliquus was used as the working microalgal strain. It is to study the growth and CO₂ fixation rate of microalgae in the circumstance of flue gas. The results showed that the microalgae grows well and the carbon reduction can each up to 50% under the flue gas.To further improve the carbon fixation of microalgae, five chemical growth regector agents was used to improve the growth and CO₂ fixation rate of microalgae. The results showed that the optimal effective concentrations of five chemical agents were:GA3 1.0 mg/ml, IAA 2.0 mg/ml, glycine 25×10-6 mg/ml, magnesium glycinate 50×10-6 mg/ml, acetic acid, 2-(2,4-dichlorophenoxy) 1.0mg/ml. Under the same condition, the best chemical agent was glycine with the concentration of 25×10-6 mg/ml, the daily average growth volume was 0.24 gd^-1l^-1, the maximum CO₂ fixation rate was 0.40 gd^-1l^-1.The mechanism of glycine to improve the microalgae growth and CO₂ fixation was futher studied by investigating the algal chlorophyll content and extracellular carbonic anhydrase content. The result showed that 25×10-6 mg/ml of glycine was the most optimum concentration, which could make the most chlorophyll content. With low concentration of CO₂, the activity of extracellular carbonic anhydrase was obviously increased.This study demonstrated the carbon fixation of microalgae was feasible, and it meets the sustainable development.