Carbon migration of microalgae from cultivation towards biofuel production by hydrothermal technology: A review

Carbon dioxide (CO2) emissions from fossil fuel burning are recognized as one of the major causes of climate change, particularly global warming. Thus, to reduce fossil fuels and CO2 emissions, it is essential to take preventative steps and investigate more tolerable energy options. Effective combining microalgae cultivation and hydrothermal liquefaction (HTL) technology can reduce CO2 emissions and the energy cost of algal biofuel production, making it more environmentally friendly. However, the carbon migration in processes must be considered prior to industry production. Therefore, this paper reviews the transformation of carbon, including the CO2 sequestration in microalgae cultivation, the carbon conversion in HTL and the CO2 emissions of algaederived biofuel. Including a summary of the conversion path and recovery of carbon, which are noticeably affected by parameters such as cultivation system, algae species, HTL reaction conditions (temperature, time and pretreatment methods) and upgrading catalyst. In addition, techno-economic assessments and environmental impact considerations on microalgae biofuel are reported.

Automated summary

This paper reviews the carbon transformation process, including CO2 sequestration in microalgae cultivation, carbon conversion in hydrothermal liquefaction, and CO2 emissions of algal-derived biofuel. It summarizes the conversion path and recovery of carbon, which are noticeably affected by parameters such as cultivation system, algae species, HTL reaction conditions, and upgrading catalyst. Techno-economic assessments and environmental impact considerations on microalgae biofuel are also reported.