Catalytic hydrothermal liquefaction of Scenedesmus sp. biomass integrated with dark-fermentation: biocrude and low-carbon fuel production in a biorefinery approach. Issue 6 (16th February 2022)

• Record Type: Journal Article
• Authors: Kopperi, Harishankar; Katakojwala, Ranaprathap; Mohan, S. Venkata
• Is Part Of: Sustainable energy & fuels. Volume 6:Issue 6(2022)
• Page Start: 1499
• Page End: 1511
• Publication Date: 2022-02-16
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/d1se02053f
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : The catalytic-HTL process integrated with dark fermentation using algal biomass as the primary feedstock was studied for production of chemicals/fuels in biorefinery mode infusing circular chemistry/economy. Abstract : Herein, we report the catalytic hydrothermal treatment of dried microalgae biomass (DAB) of Scenedesmus sp. SVMIICT1 for biocrude production employing various alkali and metal-based catalysts at 200 °C and 100 bar pressure under N2 and H2 atmospheres with twelve designed experiments. The specific influence of inert and reducing conditions together with the catalyst on the yields of bio-oil as well as the composition, off-gases and energy recovery were explored. The results depicted that H2 atmosphere and catalyst loading resulted in bio-oil with higher heating ratios (HHV: 29–37 MJ kg −1 ) and yields by hydrodeoxygenation (H/C: 1.52–1.64; O/C: 0.51–0.08). Among the catalysts, Pt/C (H2 ) afforded bio-oil with the highest calorific value (∼37 MJ kg −1 ), which is compositionally equivalent to fossil-based hydrocarbon fuels. H2 –Pt/C condition increased the saturated hydrocarbon (biodiesel) content by 38.7–89.3% of the total bio-oil. Aliphatic/aromatic hydrocarbons were predominantly observed in the bio-oil followed by carboxylic acids, furan derivatives, indanone derivatives, ketones, and substituted benzenes. The by-products of HTL (aqueous fraction, off-gases, and solid residues) were analyzed for their specific characteristics. Further, the aqueous fraction was valorized through dark-fermentation to produce bio-hydrogen and bio-methane, wherein maximum biogas yield (H2, 186 mL g −1 TOC conversion and CH4, 131 mL g −1 TOC conversion) were observed under NaOH-catalyzed conditions. This study depicts the comprehensive utilization of algal biomass for energy and chemical intermediates in a circular chemistry context.