Pyrolysis characteristics and quantitative kinetic model of microalgae Tetralselmis sp.

Pyrolysis of microalgal biomass is a potential strategy for biofuel production. In this work, the pyrolysis characteristics of microalgae, Tetraselmis sp., were systematically explored under isothermal and nonisothermal conditions. Analysis of nonisothermal decomposition of microalgae under nitrogen atmosphere at different heating rates (5, 10, 15, and 20 degrees C min(-1)) revealed that the conversion of microalgae was significantly affected by the heating rate and reached similar to 90% at approximately 500 degrees C. The mean activation energy for the pyrolysis of Tetraselmis sp. was calculated using model-free Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. Microalgae pyrolysis in a micro-tubing reactor was performed at various temperatures (360-400 degrees C) and for different reaction times (0.5-3.0 min). The results indicated that the maximum yield of biocrude (49.5 wt%) was attained during pyrolysis at 400 degrees C for 2 min. It was established that the chemical composition of the biocrude was significantly influenced by the pyrolysis conditions. A quantitative model was used to evaluate the composition of carbohydrates, proteins, and lipids in the micro algae. This facilitated the determination of individual biochemical components in the pyrolytic products. Furthermore, the time- and temperature-dependent yields of the solid residue, biocrude, and gas were predicted, providing critical information for microalgal pyrolysis design, control, and performance.

Automated summary

This study systematically explores the pyrolysis characteristics of microalgae biomass and investigates the influence of different conditions on the conversion and chemical composition of the pyrolytic products. The results show that the conversion of microalgae is affected by heating rate and temperature, and the chemical composition of the biocrude is significantly influenced by pyrolysis conditions. A quantitative model is used to determine the composition of carbohydrates, proteins, and lipids in the pyrolytic products, and the time- and temperature-dependent yields of the solid residue, biocrude, and gas are predicted.