Properties of Pyrolytic Bio-products from Microalgae (Freshwater and Oceanic Species)

Microalgae are the third generation of feedstock for bioenergy after the starch and non-edible or agriculture waste. The potential of microalgae to absorb carbon dioxide, CO2 gas from atmosphere have become the advantages for these microalgae to become one of the feedstock for bioenergy. In this work, the Isocrysis sp. (oceanic species) and Monoraphidium sp. (freshwater species) with different condition which were on aeration and flue gas have been used as the feedstock. This sample has been undergoes the ultimate and proximate analysis where are the highest moisture content has been shown by Isochrysis sp. on aeration and the highest gross calorific value was obtain from Monoraphidium sp. on flue gas. The microalgae was pyrolyzed at the heating rate 20°C/min with four different temperature which were 400°C, 450°C, 500°C, and 550°C respectively to produce three different products which were biochar (solid), bio-oil (liquid), and bio-gas (gas). The thermogravimetric (TGA) instrument has been used to analyze the microalgae powder sample at three different heating rates, 10, 20, and 40°C/min with the temperature range from room temperature to 800°C. The results indicated that there are three stages appeared during pyrolysis, moisture evaporation, primary devolatilization and residual decomposition. By using Coats-Redfern equation, correlation coefficients of different reaction models describing the pyrolysis of microalgae were predicted and the best-fit models of pyrolysis were found. The activation energies as well as frequency factors (A) from the best-fit model were calculated. From all those method used, the properties of pyrolytic bio-product from the microalgae has been determined.