On the pyrolysis of different microalgae species in a conical spouted bed reactor: Bio-fuel yields and characterization.

The aim of this work was to study fast pyrolysis of three microalgae species in a continuous bench-scale conical spouted bed reactor at 500 °C. Bio-gas, bio-oil and bio-char yields have been determined and characterized by using GC, GC/MS, elemental analyzer and SEM. Bio-oil was the main product obtained through pyrolysis of microalgae. The non-condensable gaseous stream is made up of mainly hydrogen, carbon monoxide and carbon dioxide, apart from other light hydrocarbons detected in lower concentration, as are methane, ethane, ethylene, propane and propylene. The compounds identified in the bio-oil have been categorized into hydrocarbons, nitrogen containing compounds, ketones, alcohols, acids, lactones, phenols and aldehydes. The nitrogen and carbon contents of the microalgae bio-chars are higher than those for bio-chars derived from other biomasses. Pyrolysis improved the morphology and porous structure of microalgae. Finally, the mechanism involving microalgae pyrolysis has been approached and the main reaction pathways have been proposed.

Simultaneous pyrolysis of microalgae C. vulgaris, wood and polymer: The effect of third component addition.

Due to the depletion of fossil fuels and their environmental issues, it is necessary to find energy resources which are renewable. Biomass becomes promising feedstock for bio-fuel production. The aim of this study is to investigate thermal decomposition behavior and the effect of third component on the binary mixture pyrolysis using thermogravimetric analysis (TGA). Experiments were carried out at heating rates of 10, 20 and 40°C/min from ambient temperature to 600°C. Two divided groups of peaks were observed in DTG curve of tertiary mixture which the first one was corresponded to microalgae and wood and the second one was belonged to polymer. It is stated that microalgae and wood can improve the degradation process while polymer can delay the decomposition process of mixture. Mentioned positive effect of microalgae and wood could be related to main decomposition temperature and component of microalgae and wood. On the other hand, polymer reduces weight loss of binary mixture and has negative effect of it. The kinetics analysis showed that activation energy (E) and pre-exponential factor (A) of tertiary mixture was slightly lower than that of microalgae-polymer mixture which had the lowest E and A.

Characteristics and kinetics study of simultaneous pyrolysis of microalgae Chlorella vulgaris, wood and polypropylene through TGA.

Thermal decomposition behavior and kinetics of microalgae Chlorella vulgaris, wood and polypropylene were investigated using thermogravimetric analysis (TGA). Experiments were carried out at heating rates of 10, 20 and 40°C/min from ambient temperature to 600°C. The results show that pyrolysis process of C. vulgaris and wood can be divided into three stages while pyrolysis of polypropylene occurs almost totally in one step. It is shown that wood can delay the pyrolysis of microalgae while microalgae can accelerate the pyrolysis of wood. The existence of polymer during the pyrolysis of microalgae or wood will lead to two divided groups of peaks in DTG curve of mixtures. The results showed that interaction is inhibitive rather than synergistic during the decomposition process of materials. Kinetics of process is studied by the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO). The average E values obtained from FWO and KAS methods were 131.228 and 142.678kJ/mol, respectively.