Yunming Fang

Lignin-first biorefinery: a reusable catalyst for lignin depolymerization and application of lignin oil to jet fuel aromatics and polyurethane feedstock

Lignin-first biorefinery is a novel concept, which was developed recently with great potential. This paper addresses two important issues in the lignin-first biorefinery: catalyst regenerability and lignin depolymerized product application. It was found that SiC is an effective and regenerable catalyst support, and the catalytic performance of Ru/SiC is comparable to the state-of-the-art results obtained from Ru/C used in the lignin-first biorefinery under identical conditions. Furthermore, the Ru/SiC catalyst can be regenerated by calcination without decrease in the catalytic performance. The resulting lignin oil from Ru/SiC catalyzed lignin depolymerization was then extracted by hexane, which is an optimized solvent for lignin oil upgradation based on model compound screening, and around 50xa0wt% of the hexane extract was obtained. The hexane extract was converted into aromatic hydrocarbons by ambient pressure hydrodeoxygenation over MoO3 catalyst. With a 15% blend of the resulting aromatic hydrocarbons, the jet fuel from the hydroprocessed ester and fatty acid (HEFA) meets the density requirements of the ASTM 7566 standard without compromising other required properties. The residue from hexane extraction was successfully used for preparation of rigid polyurethane foam (RPF) as an alternative to polyols of up to 50 wt%. The lignin based RPF not only reduced the use of fossil derived polyols, but also resulted in better water and flame resistance based on tentative LOI assessments. A biorefinery system was then proposed based on the technology developed in the present study.

Efficient hydro-deoxygenation of lignin derived phenolic compounds over bifunctional catalysts with optimized acid/metal interactions

Efficient hydro-deoxygenation (HDO) of lignin derived phenolic compounds was a challenging task due to the incompatibility of the phenolic feedstock and the current hydro-processing catalysts. In this paper, hydro-deoxygenation of lignin derived phenolic compounds over a series of bifunctional catalysts with different metal/acid interactions was firstly carried out. It was found that the distance between the acidic site and noble metal played an important role in the catalytic performance of phenolic hydro-deoxygenation. A highly stable bifunctional catalyst for hydro-deoxygenation of lignin derived phenolic compounds was obtained through simple selective deposition of Pt on alumina in a commonly used Al2O3-ZSM-5 nanocomposite. The bifunctional catalyst retained its complete deoxygenation capacity for more than 500 h. The catalyst can also be used for the HDO of various phenolic model compounds and real bio-oil derived from lignin. A correction of the generally accepted “the closer the better” criterion in metal/acid bifunctional catalysts when used in bio-oxygenate HDO was also discussed.

Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating

BackgroundThe production of fuels and chemicals from renewable resources is increasingly important due to the environmental concern and depletion of fossil fuel. Despite the fast technical development in the production of aviation fuels, there are still several shortcomings such as a high cost of raw materials, a low yield of aviation fuels, and poor process techno-economic consideration. In recent years, olefin metathesis has become a powerful and versatile tool for generating new carbon–carbon bonds. The cross-metathesis reaction, one kind of metathesis reaction, has a high potential to efficiently convert plant oil into valuable chemicals, such as α-olefin and bio-aviation fuel by combining with a hydrotreatment process.ResultsIn this research, an efficient, four-step conversion of plant oil into bio-aviation fuel and valuable chemicals was developed by the combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating. Firstly, plant oil including oil with poor properties was esterified to fatty acid methyl esters by an enzyme-catalyzed process. Secondly, the fatty acid methyl esters were partially hydrotreated catalytically to transform poly-unsaturated fatty acid such as linoleic acid into oleic acid. The olefin cross-metathesis then transformed the oleic acid methyl ester (OAME) into 1-decene and 1-decenoic acid methyl ester (DAME). The catalysts used in this process were prepared/selected in function of the catalytic reaction and the reaction conditions were optimized. The carbon efficiency analysis of the new process illustrated that it was more economically feasible than the traditional hydrotreatment process.ConclusionsA highly efficient conversion process of plant oil into bio-aviation fuel and valuable chemicals by the combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreatment with prepared and selected catalysts was designed. The reaction conditions were optimized. Plant oil was transformed into bio-aviation fuel and a high value α-olefin product with high carbon utilization.