https://eprints.whiterose.ac.uk/82741/1/1-s2.0-S0960852414013911-main.pdf

Hydrothermal liquefaction of biomass: Developments from batch to continuous process

The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, but as yet there is no successful economically viable commercial system producing biofuel. However, the majority of the research has focused on producing fuels from microalgae rather than from macroalgae. This article briefly reviews the methods by which useful energy may be extracted from macroalgae biomass including: direct combustion, pyrolysis, gasification, trans-esterification to biodiesel, hydrothermal liquefaction, fermentation to bioethanol, fermentation to biobutanol and anaerobic digestion, and explores technical and engineering difficulties that remain to be resolved.

/pdf/macroalgae-derived-biofuel-a-review-of-methods-of-energy-3he3dab8ac.pdf

Macroalgae-Derived Biofuel: A Review of Methods of Energy Extraction from Seaweed Biomass

Hydrothermal liquefaction of agricultural and forestry wastes: state-of-the-art review and future prospects

https://eprints.whiterose.ac.uk/93010/2/Green%20manuscript.pdf

A comparison of product yields and inorganic content in process streams following thermal hydrolysis and hydrothermal processing of microalgae, manure and digestate.

Impact of hydrothermal carbonization conditions on the formation of hydrochars and secondary chars from the organic fraction of municipal solid waste

Influence of pH on hydrothermal treatment of swine manure: Impact on extraction of nitrogen and phosphorus in process water.

The composition of syngas and process water from the supercritical water gasification of macroalgae has been investigated. The potential for using the process water as a source of nutrients for microalgae cultivation was assessed. Saccharina latissima, harvested across the four seasons was gasified in a batch reactor at 500°C and 36 MPa to assess the influence of biochemical content and ash on syngas composition. In addition, summer harvests of four different macroalga were gasified with ruthenium catalyst (Ru/Al2O3). The molar yields of hydrogen and C1-C4 gases from S. latissima increased by 30% in the presence of Ru/Al2O3 with a maximum gasification efficiency of 92% compared with work without these catalysts. Following a series of dilutions, the process water from catalyzed gasification of S. latissima was used in cultivation trials of Chlorella vulgaris and compared to standard growth media. The results indicate the potential to recover process waters from gasification of macroalgae in nutrient management for microalgae.

Macroalgae supercritical water gasification combined with nutrient recycling for microalgae cultivation

Despite being the regions with the least levels of carbon emissions in the world, African countries are facing unique challenges on climate change, increased carbon emission levels and the need for environmental governance improvement. This study, therefore, examined the implications of economic growth and governance on CO2 emissions in West Africa. Specifically, the study investigated the role of governance in moderating the effect of economic growth on CO2 emissions in West Africa. The study utilized data for 16 West African countries from 2000 to 2020 in an unbalanced panel data framework. Empirical analyses were conducted using the Instrumental Variable Fixed Effects estimator with Driscoll and Kraay Standard Errors, as well as the Instrumental Variable Quantile Regression in order to account for serial correlation, endogeneity and conditional heteroskedasticity. The following conclusions were drawn from the results. First, economic growth significantly increases CO2 emissions in the region with the Environmental Kuznet Curve hypothesis present. Second, the quantile regression estimates reveal that the effect of economic growth on CO2 emissions is higher in countries where the initial level of carbon emissions is considerably high. Third, the results further show that in the presence of improved governance quality, economic growth does not significantly influence CO2 emissions in the region. Fourth, political stability and regulatory quality were the only indicators of governance that significantly impacted environmental pollution in the region. Finally, we found that other factors such as trade, urbanization, and renewable energy also significantly influenced CO2 emissions in the region. The study concludes by highlighting the importance of governance in moderating the effect of economic growth on CO2 emissions, as well as the importance of heterogeneous analysis for understanding the dynamism in economic relationships.

U. Ekpo

Papers

A comparison of product yields and inorganic content in process streams following thermal hydrolysis and hydrothermal processing of microalgae, manure and digestate.

Influence of pH on hydrothermal treatment of swine manure: Impact on extraction of nitrogen and phosphorus in process water.

Macroalgae supercritical water gasification combined with nutrient recycling for microalgae cultivation

Economic Growth, Governance and CO2 Emissions in West Africa