(768a) Hydrothermal Liquefaction of Microalgae and Co-Product Development

Hydrothermal Liquefaction proves to be one of the promising process among thermochemical conversion technologies in the production of liquid transportation fuels. The red alga Galdieria sulphuraria was liquefied in a stainless-steel batch reactor and the influence of biomass loading, residence time and temperature was assessed. A maximum biocrude oil yield of 35.0 wt% was obtained at 300 °C and at a solid loading ratio of 20 % for 30 minutes residence time. Various analytical techniques were employed to analyze the valuable chemical components present in the liquefied products (bio-oil, biochar, water soluble compounds, and gaseous phase). Analysis of biochar using ICP-OES and elemental analyzer indicated the presence of macronutrients (nitrogen 6.36 mg & phosphorus 6.59 mg per gram of biochar), which are re-utilized to cultivate microalgae. Biochar was leached for macronutrients at different pH conditions (1.0 – 7.0) to estimate the efficiency and study the growth characteristics of microalgae. Gas Chromatography Mass spectrometry (GC-MS), ¹H NMR spectroscopy and calorimetric techniques were also used to analyze the products. Energy recovery was calculated through the ultimate and proximate analysis of the products.