Pyrolysis characteristics and products distribution of haematococcus pluvialis microalgae and its extraction residue.

Pyrolysis characteristics of microalgae (MA) and its chemical extraction residue (MR) were evaluated and compared using a thermal analyzer and a tube furnace reactor. Results showed that the pyrolysis process of MA and MR can be divided into three stages, which corresponded to the volatile of free water, the decomposition of organic compounds and the stabilization of residues, respectively. Due to the removal of lipids after MA extraction, only one weight loss peak was recorded in the second stage of MR. Using the methods of Friedman, FWO and Starink, the average activation energies of MA and MR were calculated as 204.72 and 178.51 kJ/mol, respectively. Pyrolysis oil, gas, and char products were obtained from both MA and MR pyrolysis. Main gas products from pyrolysis of MA and MR contained CO 2 , CO, H 2 and CHs. Compared with MA pyrolysis, the relative contents of CHs were lower (<59%) during MR pyrolysis, but the contents of CH 4 were higher. Results for higher hydrocarbons (C 4-6 , C 6+) were lower in MR than in MA pyrolysis. MR pyrolysis can be a promising method for the waste treatment with high value-added pyrolysis liquid and gases products. Image 1 • Pyrolysis kinetics of MA and MR were investigated and compared. • Distribution of pyrolysis products was comprehensively studied. • Average activation energies of MA and MR were 63.29 kJ/mol and 50.28 kJ/mol. • Higher hydrocarbons (C 4-6 , C 6+) were lower in MR than in MA pyrolysis. [ABSTRACT FROM AUTHOR]