Production of biocoke from microalgae powder

Abstract

Biocoke has been invented to replace commercial coke in order to reduce the consumption of fossil fuels. However, the main target of the feedstock has been limited to plant and wood biomass, while algal biomass is rarely used. This work evaluated four microalgae species: Chlorella, Nannochloropsis, Diatoms, and Aurantiochytrium as the feedstocks to produce biocokes. The production of the biocoke was set to 100°C at 20 MPa for 6 mins 20 secs. Based on visual observation, the color of the biocokes produced was darker than the microalgae powder due to the Maillard reaction. This study suggested that the Chlorella and Nannochloropsis biocoke have the potential to produce the biocoke due to their oleaginous characteristic. Nannochloropsis had a higher apparent density than Chlorella biocoke. However, the Chlorella had a higher compression strength of 37.55MPa, compared to Nannochloropsis (27.70MPa). Meanwhile, Aurantiochythrium biocoke had an irregular shape and was sticky due to the high lipid content in the species. The Diatoms biocoke was hard but chalky due to its silica shell on the microalgae cell. Therefore, the Aurantiochythrium and Diatoms were not suitable for producing the biocokes.