Fast pyrolysis of LERDADEs for renewable biofuels

The lipid-extracted residues of Desmodesmus sp. cultivated in anaerobically digested effluents (LERDADEs) were determined in real time using a thermogravimetric analyser and pyrolysis-gas chromatography-mass spectrometry coupling technology over a range of temperature (300-800 degrees C). The composition analysis results indicated that LERDADE has potential for energy application due to its high carbon content and relatively low nitrogen content. The main decomposition temperature of LERDADE was 319.9 degrees C, at which up to 68.4% of the mass was lost. The fast pyrolysis of LERDADE at 800 degrees C produced the maximum yield (36.6%) of bio-oil compared with 29% at 700 degrees C. However, the number of harmful pollutants (polycyclic aromatic hydrocarbons and nitrogen compounds) released at 800 degrees C (41.7%) was much higher than that released at 700 degrees C (28.3%), which caused a relative increase of 32.1%. Considering the reasonably high bio-oil production and minimum pollutant emission, a lower temperature (similar to 700 degrees C) was found to be optimum for producing biofuel from LERDADE.