Research On Fast Pyrolysis Characteristics Of Chlorella Vulgaris And Dunaliella Salina

Microalgae are a diverse group of aquatic, photosynthetic organisms which are typicallyunicellular. Microalgae have the potential to revolutionize biotechnology in a number ofareas including nutrition, aquaculture, pharmaceuticals, and biofuels. As a new type ofenergy crop, microalgae has many advantages over other feedstocks, such as short growthcycle, high photosynthetic efficiency, no occupying arable land, carbon capture and wastewater/gas treatment. In recent years, microalgal biodiesel is the main developing technicalroute, but there are many problems in the entire process, such as low lipid content,incomplete extraction and pollution control from the extraction reagent recovery resulting inpoor economy. Therefore, fast pyrolysis gradually become an alternative technical route.Thermal decomposition of two kinds of microalgae (Chlorella vulgaris and Dunaliellasalina) were performed using TGA. Effects of heating rate on pyrolytic chracteristics wereinvestigated, and thermal decomposition kinetics were analysed as well.Furthermore, fast pyrolysis experiments were carried out in a fixed bed reactor, and themain products were pyrolytic oil and pyrolytic char. Highest yields of pyrolytic oil were60.67%and64.87%respectively for Chlorella vulgaris and Dunaliella salina at500℃.Detailed research on pyrolytic products properties were carried out. The characteristic ofbio-oil from microalgae pyrolysis, including chemical composition, water content, density,acidity and heating value were investigated as well as the influence of pyrolytic temperature,carrier gas flow rate and catalyst. It is found that the microalgae pyrolytic oil had a richcontent in alkanes, alkenes, alkines and especially nitrogenous compounds. Compared withbio-oil from common biomass, the microalgae oil had a lower oxygen content, a lower watercontent, a lower total acid number and a higher heating value. In the presence of Na2CO3, theoverall quality of pyrolytic oil was much better, with a lower water content, a lower totalacid number and a higher heating value. Additionally, the microalgae char had a highinorganic content (Na, Mg, Ca, K, Fe), suggesting it maybe suitable to provide nutrients forplants or be used as a kind of neutralizing reagent to improve acid soil.