Study on microwave pyrolysis and production characteristics of Chlorella vulgaris using different compound additives

Pyrolysis characteristics and bio-oil of Chlorella vulgaris were investigated under SiC and ZnO (SZ) mixture (compound additive) with various mixing ratios (S/Z = 10:0, 7:3, 5:5, 3:7, 0:10) and addition amounts (5%, 10%, 15%) by thermogravimetric analysis and GC-MS. At three experimental groups of 10% compound additive, as ZnO in compound additive increased, maximum weight loss rate ((R)p) increased, the time (t(p)) corresponding to R-p and the weight stabilization time (t(f)) first decreased and then increased, while average rate of weight loss (R-a) and total weight loss (M) first increased and then decreased; maximum temperature rising rate (H-x) and average rate of temperature rising (H-g) increased, while the time (t(x)) corresponding to H-x decreased. Compound additives reduced the bio-oil yield, increased the gas yield, and reduced the acid compounds in bio-oil. Besides, it might promote the production of alicyclic hydrocarbons and oxygen/nitrogen-containing long-chain compounds.