Shanghuan Feng

Investigation of aqueous phase recycling for improving bio-crude oil yield in hydrothermal liquefaction of algae

In this study, the aqueous phase obtained from catalytic/non-catalytic hydrothermal liquefaction (HTL) of Chlorella vulgaris was recycled as the reaction medium with an aim to reduce water consumption and increase bio-crude oil yield. Although both Na2CO3 and HCOOH catalysts have been proven to be effective for promoting biomass conversion, the bio-crude oil yield obtained from HTL with Na2CO3 (11.5wt%) was lower than that obtained from the non-catalytic HTL in pure water at 275°C for 50min. While, the HCOOH led to almost the same bio-crude yield from HTL (29.4wt%). Interestingly, bio-crude oil yield obtained from non-catalytic or catalytic HTL in recycled aqueous phase was much higher than that obtained from HTL in pure water. Recycling aqueous phase obtained from catalytic HTL experiments resulted in a sharp increase in the bio-crude oil yield by 32.6wt% (Na2CO3-HTL) and 16.1wt% (HCOOH-HTL), respectively.

Highly efficient organosolv fractionation of cornstalk into cellulose and lignin in organic acids

In this study, effects of fractionation solvents, catalysts, temperatures and residence time on yields, purity and chemical composition of the products were investigated at the solid/solvent ratio of 1:5 (g/g). It was revealed that mixture of acetic acid/formic acid/water at the ratio of 3:6:1 (v/v/v) resulted in crude cellulose and lignin products of relatively high purity. The use of HCl catalyst contributed to a high crude cellulose yield, while H2SO4 showed an adverse effect on cellulose yield. However, both of these acidic catalysts contributed to much lower hemicellulose contents in the resulted crude cellulose products compared with those obtained without a catalyst. Fractionation at 90°C for 180min in mixed solvents of acetic acid/formic acid/water (3:6:1, v/v/v) with or without catalyst produced crude cellulose with very low residual lignin contents (<4%).

Preparation and characterization of bark-derived phenol formaldehyde foams

Bark-derived oils produced by hydrothermal liquefaction of outer and inner white birch bark in an ethanol–water (1 : 1, w/w) mixture were utilized for the synthesis of bio-based phenol formaldehyde (BPF) foamable resole resins with different levels of phenol substitution ratios (25 wt% and 50 wt%). Then BPF foams were successfully produced by mixing a blowing agent, a surfactant and a curing agent with the synthesized BPF resoles. The FT-IR analysis showed that BPF foamable resoles and BPF foams both have a very similar structure as a conventional phenol formaldehyde (PF) resole resin and foam. The obtained BPF foams displayed satisfactory compressive strength, elastic modulus, and thermal conductivity. The inner bark-derived oil was found to be more suitable than the outer bark-derived oil for the production of BPF foams, as the former resulted in foams with lower densities and tinier cell structure.