Jie Yang

Title : The effect of additives (Sea Salt & Na2co3) on hydrothermal liquefaction of biomass for biocrude production and intelligent prediction

Abstract:

Hydrothermal liquefaction (HTL) utilizes subcritical/supercritical water as a reaction medium to convert biomass into biocrude, presenting a promising avenue for mitigating greenhouse gas emissions. However, prevailing research predominantly employs freshwater as the reaction medium, posing a significant challenge in terms of resource availability. We investigated the potential of seawater as an alternative medium for HTL, with a particular focus on elucidating the mechanistic role of sea salt in the HTL process of biomass. The primary component of sea salt, sodium chloride (NaCl), is examined in detail to evaluate the influence of sea salt in relation to NaCl. While sodium carbonate (Na₂CO₃) is commonly used as a catalyst in real biomass hydrothermal liquefaction, its impact on individual biomass components is not well-explored. Therefore, study delves into the role of Na₂CO₃ in HTL of biomass model components under varying conditions. Four types of biomass components—carbohydrate, lignin, protein, and lipid—are subjected to HTL under different concentrations of additives and temperature conditions. Subsequently, machine learning algorithms are employed to create a highly accurate predictive tool

The findings reveal that in the HTL of lignin and protein, sea salt demonstrates a promotional effect, augmenting biocrude formation. Compared with NaCl, it is observed that these minor constituents in sea salt have minimal effects on lignin HTL but contribute to increased biocrude yields in carbohydrate HTL compared to NaCl. Compared with freshwater Na₂CO₃ at 5wt.% enhances carbohydrate degradation into biocrude and aqueous-gaseous products (AG), aligning with previous findings on carbohydrate-rich feedstocks. Although Na₂CO₃ has a marginal effect on lignin HTL, it negatively influences lipid HTL. At 5wt.% and 13.5wt.% Na2CO3 concentrations, the biocrude yield decreases from 95.6% to less than 10%, simultaneously increasing the AG yield to approximately 90%. This is attributed to the interaction of lipid decomposition intermediates (fatty acids) with sodium cations, resulting in water-soluble soap. For protein HTL, a low Na2CO3 concentration (5wt.%) has no significant impact on product formation, but excessive Na2CO3 (27wt.%) converts a substantial portion of biocrude into AG. We employed machine learning algorithms, leading to a highly accurate predictive tool with an R² value exceeding 0.94, surpassing conventional mathematical methods. This software tool facilitates rapid estimation of additive-involved HTL biocrude yield and offers recommendations for additive type, loading, and optimal HTL conditions based on the feedstock.

In summary, this research provides fundamental insights into the role of additives in the HTL product formation pathway, presenting an intelligent and precise prediction model for HTL biocrude yield. These advancements contribute to the development of more efficient and sustainable bioenergy production processes.

Audience Take Away

• HTL converts biomass to biocrude for emissions reduction.
• Seawater, NaCl's role in biomass conversion explored.
• Na₂CO₃ impact on individual biomass studied.
• NaCl enhances biocrude in lignin and protein HTL.
• ​​​​​​​Machine learning algorithms predict additive-involved HTL biocrude yield

Biography:

Dr. Yang joined the research group of Prof. Quan (Sophia) He studied Agriculture at Dalhousie University, Canada, and graduated as MS in 2016. He received his PhD degree in chemical engineering, in 2019, at the same institution. After one year of instructor fellowship at Dalhousie University, Canada he obtained the position of Associate Professor at the Minjiang University, China, adjunct at Dalhousie University, Canada. He leads the Sustainable Utilization of Marine Green Resources Lab and has published over 30 research articles in SCI(E) journals. His research interests lie in Green and sustainable biorefinery, biofuels productions, hydrothermal liquefaction, biochemicals/materials.