Study on combustion and emission characteristics of microalgae and its extraction residue with TG-MS

Experimental study on combustion and emission characteristics of microalgae (M) and the extraction residue (MR) was carried out on a coupled thermogravimetric and mass spectrometer system (TG-MS). TG results showed that combustion process of M and MR can be divided into three stages, including water volatilization, the release and combustion of proteins, carbohydrates and lipids, and minerals decomposition. As the heating rate increased, thermal hysteresis was occurred during combustion of M and MR, especially for M. Friedman method, FWO method and Starink method were used to calculate the apparent activation energy during combustion of M and MR. As the conversion rates increased, the apparent activation energy of M and MR showed different trends. The average apparent activation energy of M and MR in the main combustion stage was 183.41 kJ mol(-1) and 144.41 kJ mol(-1), respectively. MS results demonstrated that the release of nitrogen-containing compounds of M was more than MR while the release of sulfur-containing compounds was similar during M and MR combustion. (C) 2019 Elsevier Ltd. All rights reserved.