Pyrolysis and gasification of macroalgae Enteromorpha prolifera under a CO2 atmosphere using the thermogravimetry–Fourier transform infrared spectroscopy technique

Abstract

Non-isothermal pyrolysis and gasification of Enteromorpha prolifera (also known as Ulva prolifera) under a CO2 atmosphere were investigated by thermogravimetry analysis. The gaseous products were measured online with Fourier transform infrared spectroscopy coupled with thermogravimetry. The kinetic parameters of pyrolysis and gasification reactions were obtained using the Coats–Redfern method. The experimental results showed that Enteromorpha prolifera had two derivative thermogravimetry peaks centered at 240 and 800°C, indicating the pyrolysis of organics and gasification of char, respectively. Carboxylic acids, ethers, and alcohols were the dominating condensable products generated from pyrolysis between 230 and 300°C. H2O, CH4, and aliphatic hydrocarbons were also formed in this temperature range, and they were also continuously released at higher temperatures, indicating further polymerization of the freshly generated pyrolytic char. CO was mainly produced between 700 and 900°C, and its yield was much higher than that of the pyrolytic gaseous products. The Ginstling equation (the D4 model) proved to be the most probable mechanism function for both the pyrolysis and gasification stages, with activation energies of 138.30 and 93.43 kJ mol−1, respectively.