Effect of Wet Torrefaction on Thermal Decomposition Behavior of Microalga Chlorella vulgaris ESP-31

In this work, thermal decompositions of wet torrefied microalga during pyrolysis and combustion are investigated. Microalga Chlorella vulgaris ESP-31 was first subjected to wet torrefaction with microwave-assisted heating. Then, the thermal decompositions of the raw and torrefied microalgae are studied by means of a thermogravimetric analyzer in nitrogen and synthetic air to simulate pyrolysis and combustion process, respectively. The results show that carbohydrate and protein are degraded to some extent during WT. In addition, thermal reactivity of lipid is also changed after WT. The changes in the microalgal composition affect the intensity and location of the corresponding peaks during pyrolysis and combustion. Moreover, the char produced from the raw microalga is more reactive and less stable than those from the torrefied microlagae.