The Effects Of Different Cultivation Conditions On Pyrolysis Products Of Energy Microalgae

Developing bioenergy is one of the effective ways to alleviate the pressure of the global energy and environment. Chlorella was cultivated in different temperature, light intensity, light cycle, ventilation, carbon source and carbon source concentration in culture experiment.And then chlorella cultivated in different conditions was pyrolysed. We studied the effects of different culture conditions and nutrient on chlorella growth rate, cell composition and pyrolysis products.After that culture conditions was optimized for large-scale production. The main results were as follows:(1) The results showed that the optimum growth temperature of chlorella was25℃;and the light saturation point was in the vicinity of2000lux; the optimal light cycle was12L:12D. Ventilation cuold greatly promote growth of chlorella,The best ventilation volume of chlorella was1L/min. Compared with chlorella without ventilation, the biomass of chlorella with a ventilation volume of1L/min was increased16times. Carbon sources affected growth of chlorella prominently(P<0.05). With glucose as a carbon source, chlorella had the biggest biomass of6.0445g/L and the shortest growth cycle. Biomass of chlorella with glucose as carbon source was2.4and3.7times as much as that of chlorella with CO2and Na2CO3as carbon source. the optimum concentration of glucose was20g/L.(2) The results showed that protein and starch content of chlorella increased with the culture temperature increasing, whereas carbohydrate and fat content as well as the unsaturated dergee of fatty acid decreased significantly. sugar content increased with the light intensity increasing, whereas protein and fat content as well as the unsaturated dergee of fatty acid decreased, and starch content was no such correlation. Protein content decreased as the illumination time increased. When the light cycle was12L:12D, sugar content was the highest while the starch content was minimum. Fat content handly influenced by light cycle. The unsaturated dergee of fatty acid increased as the illumination time decreased. Compared with chlorella cells with ventilation, the fat and starch content of chlorella cells without ventilation was higher and the unsaturated dergee of fatty acid was significantly lower.And proper ventilation (1L/min) could effectively promote synthesis of protein and sugar. Compared with inorganic carbon source, chlorella cells cultured with organic carbon source—glucose had higher sugar, starch, fat content and lower protein content. The index of unsaturated fatty acid significantly increased in C02treatment group, The content of unsaturated fatty acid was57.38%. High glucose concentration could significantly promote synthesis of carbohydrate and inhibit synthesis of protein. While concentration of glucose had no significant effect on fat content of chlorella. Unsaturated fatty acid content increased with glucose concentrations increasing. Unsaturated fatty acid content made up over60%of the total fatty acids in30g/L glucose treatment group.(3)The results showed that culture conditions had significant effects on pyrolysis products of chlorella. The oil yield and ratio of hydrocarbon had some relations with the growth status of chlorella, namely chlorella which grew in optimal conditions also could obtain higher oil yield and ratio of hydrocarbon.Through the above analysis, We know that the optimal culture conditions of chlorella were as follows:Cultivation temperature was25℃; Light intensity was20001ux; Light cycle was12L:12D;Ventilation was lL/min,;Carbon source was glucose,;Glucose concentration was20g/L. chlorella which was cultivated in this conditions could obtain higher oil production rate and more hydrocarbon production after pyrolysis.