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This research evaluates the thermodynamic performance of three polylactic acid (PLA) biorefinery scenarios, utilizing Eucheuma cottoni residue (ECR), as raw material. The thermodynamic properties of three biorefinery scenarios were obtained through Aspen Plus® V14 to conduct exergy analysis. Ultrasonic-assisted molten salt hydrates minimized the amount of ECR needed by 80.8 % to produce 1000 kg/h of PLA. The fermentation unit exhibited the highest destroyed exergy in Scenarios 1 and 2, while it was the combined heat and power (CHP) unit for Scenario 3. Scenario 3, integrated with power generation and a proper waste management system, had the highest functional exergy efficiency (22.33 %). Exergoeconomic analysis was conducted after obtaining results from exergy analysis. The unit exergoeconomic cost of PLA was 188 USD/GJ in Scenario 1, while it was 187.88 USD/GJ in Scenarios 2 and 3. The unit exergoeconomic cost of electricity and fertilizer is 35.91 USD/GJ and 250.31 USD/GJ, respectively. Pretreatment and hydrolysis unit had the highest exergoeconomic factor. LA recovery unit of all biorefinery was found to have an adequate level of exergoeconomic factor. • Poly (lactic acid) production from macroalgae waste was evaluated thermodynamically. • Raw materials and energy demand were reduced with MSH pre-treatment. • LAB cultivation subunit has the highest exergy losses in all biorefinery scenarios. • Scenario 3 had the highest functional exergy efficiency of 22.33 %. • The unit exergoeconomic cost of Scenario 3 was 187.88 USD/GJ. [ABSTRACT FROM AUTHOR]

This study evaluated the exergetic and exergoeconomic performance of three L-lactic acid (L-LA) production scenarios. All three scenarios produced L-LA from red macroalgae waste, Eucheuma cottonii residue (ECR) with the same species of enzymes, and lactic acid bacteria (LAB). Scenario 1 is the biorefinery process for the L-LA. Scenario 2 is the biorefinery process for the L-LA with fertilizer production and wastewater treatment. Scenario 3 is the polylactic acid (PLA) biorefinery process with fertilizer production and wastewater treatment. From the study, the total production rate for L-LA was 5194 kg/hr, with a total consumption rate of 12079 kg/hr for ECR. In addition, the production rates of organic fertilizer and reused water were 1609 and 1233 kg/hr, respectively, for scenario 2. Then, the production rate of the PLA was 4142 kg/hr for scenario 3. From the comparison, the energy consumption was increased due to the increased demand for process and equipment (from 28272.53 kW to 30296.15 kW). From the exergetic analysis aspect, the highest contributor to the exergy loss was the simultaneous saccharification and fermentation (SSF) unit, totaling 18875.62 kW. For the exergoeconomic aspect, the SSF unit also contributed the highest exergy destruction cost rate (average 70%). The study results provide theoretical guidance for exergetic and economic performance improvement in future L-LA and PLA production. [Display omitted] • SSF subunit contributed the highest exergy loss in all biorefinery scenarios. • The exergoeconomic factor for SSF was the lowest among all biorefinery scenarios. • Scenario 3 is PLA biorefinery with fertilizer production and wastewater treatment. • Scenario 3 accounted for the highest functional exergy efficiency of 19.54%. • The normalized exergy destruction of Scenario 3 was calculated as 0.45. [ABSTRACT FROM AUTHOR]

This paper evaluates the thermodynamic performance of three different l-lactic acid (LLA) biorefinery scenarios, utilizing macroalgae cellulosic residue, namely Eucheuma denticulatum residues (EDRs), as raw materials. To establish exergy analysis, the thermodynamic properties of each biorefinery scenario was obtained through process simulation using Aspen Plus® V10. It was found that microwave-assisted autohydrolysis (MAA) was feasible in minimizing the amount of EDRs needed by 70.2% to produce 1000 kg/h of LLA. The fermentation unit, wastewater treatment (WWT) unit, and combined heat and power (CHP) unit were ranked top three for the occurrence of exergy destruction. Both the LLA recovery unit (99.37%) and MAA pretreatment unit (99.68%) were found to be highly exergetically efficient. Among the three scenarios, Scenario III , which was integrated with power generation and a proper waste management system, had the highest functional exergy efficiency (22.12%) and normalized exergy destruction (0.73). It demonstrated the highest functionality due to the prevention of material losses by converting waste streams into value-added products and reducing reliance on fossil-fuel derived energy for plant operation. The valuable information from exergy analysis provides theoretical guidance for performance enhancement in a macroalgae-based biorefinery to produce LLA, either with process integration or technology advancement. [Display omitted] • l-lactic acid production from macroalgae waste was evaluated thermodynamically. • Raw materials and energy demand were reduced with MAA pre-treatment. • PSSF subunit exhibited the highest exergy losses in all biorefinery scenarios. • Scenario III had the highest functional exergy efficiency of 22.12%. • The normalized exergy destruction of Scenario III was determined as 0.73. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microalgae-derived biochar has demonstrated great potential for net zero emissions. • Biochar enables circular bioeconomy via waste utilization and carbon sequestration. • Biotechnology advances resolve bottleneck in microalgal biochar commercialisation. The rapid expansion of industrialization and continuous population growth have caused a steady increase in energy consumption. Despite using renewable energy, such as bioethanol, to replace fossil fuels had been strongly promoted, however the outcomes were underwhelming, resulting in excessive greenhouse gases (GHG) emissions. Microalgal biochar, as a carbon-rich material produced from the pyrolysis of biomass, provides a promising solution for achieving net zero emission. By utilizing microalgal biochar, these GHG emissions can be captured and stored efficiently. It also enhances soil fertility, improves water retention, and conduct bioremediation in agriculture and environmental remediation field. Moreover, incorporating microalgal biochar into a zero-waste biorefinery could boost the employ of biomass feedstocks effectively to produce valuable bioproducts while minimizing waste. This contributes to sustainability and aligns with the concepts of a circular bioeconomy. In addition, some challenges like commercialization and standardization will be addressed in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bimetallic catalyst of W-Ni on porous support yields high EG, up to 89% • Repeated use of catalyst causes metal leaching, oxidation, sintering and deposit. • The highest reusability of 34 runs was recorded for Ru/AC + H 2 WO 4 catalysts. • Impacts of impurities in biomass (i.e. lignin, sulfur, Al, Mg and Fe) are analyzed. • Pressure swing and extractive distillations reduce energy demand. Ethylene glycol (EG) is one of the most sought-after industrial compounds. High global demand necessitates for a production of up to 28 million metric tons EG a year. Reaction pathway for fossil fuel derived EG may be relatively simpler, but it remains a finite resource and is notorious for greenhouse gas emission. The increasing awareness for sustainable development and security of raw material has prompted researchers to explore novel ideas for production of EG from renewable feedstock. The abundance of lignocellulosic raw material naturally positions it as a desirable substitute to its petrochemical counterpart. This paper reviews recent progress in valorization of biomass via catalytic conversion through a broader lens, encompassing the vital aspects for commercialization of process technology. An in-depth analysis of three critical inter-related subjects for sustainable EG production, namely the catalytic system performance, effects of impurities in biomass and catalyst reusability in the harsh hydrothermal reaction is presented. Probing further into post-reaction process, purification strategies of close boiling points polyol mixture product through this bio-route are assessed. Finally, the challenges and prospects of scaling-up the technology are appraised. [ABSTRACT FROM AUTHOR]

Production of third-generation bioethanol from macroalgae cellulosic residue (MCR) has received increasing interest from researchers to utilize waste for valuable product creation effectively. In this study, a techno-economic assessment to produce anhydrous bioethanol from MCR in Malaysia had been conducted by using Aspen Plus V10 and other computer-aided softwares. Kota Kinabalu Industrial Park at Sabah was identified and selected as a proper location to produce the anhydrous bioethanol based on a framework structured by the Triple Bottom Line. The overall results from the present study showed that 15833.3 kg/h of MCR was required to produce 7626 kg/h of anhydrous bioethanol. It was also found that the energy utilization could be reduced up to 32% with net energy ratio of 0.53 after implementing the Heat Exchanges Networks Synthesis and a series of process optimization. In 20 years of plant life, the pay-back period was 8 years with an internal rate of return of 23.17%. The minimum selling price of anhydrous bioethanol was estimated to be $ 0.54/kg and able to compete with the market prices of bioethanol derived from other feedstocks. • Perform optimized design of bioethanol production from algae waste using Aspen Plus. • Compute economic feasibility in producing 183 tonnes anhydrous bioethanol annually. • Identify best location for plant in Malaysia explicitly using Triple Bottom Line (TBL) scoring system. [ABSTRACT FROM AUTHOR]