Unexplored Areas of Direct Solvolytic Liquefaction of Lignocellulosic Biomass

Bahlo, Rune L.; Hursthouse, Andrew; Sievers, Anika; Willner, T.

doi:10.1002/cite.201700076

Cited by 1 publication

(3 citation statements)

References 45 publications

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“…232 However, it is noteworthy that most solvolysis research is still limited to batch and semicontinuous processes. 233 Two recent works on the role of solvents in thermochemical biomass conversion can be found from Castellvi ́Barneś et al and Shuai and Luterbacher. 67,234 Solvent effects can be divided into two categories: (1) the effect on feedstock solubility and (2) the effect on solvolysis chemical thermodynamics.…”

Section: Effect Of Solventsmentioning

confidence: 99%

“…Two advantages of this type of biomass solvolysis process, from Isa et al, are quoted directly: “(1) The chosen solvent could dilute the concentration of the products and prevent the cross-linked reactions between hydrocarbon and aromatic compounds generating tar compounds, and (2) relative low reaction temperature (less energy consumption) in comparison with other thermochemical processes (pyrolysis and gasification)” . However, it is noteworthy that most solvolysis research is still limited to batch and semicontinuous processes …”

Section: Effect Of Solventsmentioning

confidence: 99%

“…There still remain significant challenges at every scale for effective modeling of char formation . However, as shown among some computational studies, results for lignin depolymerization can still be abstracted post hoc into lumped parameters following more highly detailed simulation. − ,,, In this way, it is possible to employ computational microkinetic algorithms/simulations, with a tremendously high level of detail, to derive pseudokinetic lumped parameters that are verifiable using experimental techniques for both pyrolytic and solvolytic lignin liquefaction.…”

Section: From Microkinetics To Pseudokineticsmentioning

confidence: 99%

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A Review on Lignin Liquefaction: Advanced Characterization of Structure and Microkinetic Modeling

Terrell

Dellon

Dufour

et al. 2019

Ind. Eng. Chem. Res.

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Lignin liquefaction microkinetics is a move toward a more first-principles (i.e., ab initio)-based understanding at the molecular level in reaction engineering. While the microkinetic modeling of reactions to obtain kinetic rate parameters of chemical reactions have been widely used in the field of gas phase combustion and heterogeneous catalysis, this approach has not been as thoroughly developed in the area of biomass thermochemical reactions (e.g., lignin pyrolysis, hydrothermal liquefaction). The difficulties in establishing the structure of complex heterogeneous materials, like lignin, is perhaps the main challenge in developing rational microkinetic descriptions of biomass thermochemical reactions. In this manuscript, we review the current state of the art and the challenges to develop microkinetic models for lignin liquefaction technologies (e.g., pyrolysis, hydrothermal liquefaction, solvolysis). A general strategy for the development of microkinetic models for lignin liquefaction technologies is discussed. The first hurdle is to obtain sufficiently rich experimental data of lignin underlying polymeric structure and methodologies to use this data to build realistic lignin structural representations. Some analytical techniques for lignin structural characterization and their associated data, as well as a correlation for calculating the degree of macromolecular lignin branching, are discussed. The presence of small lignin oligomeric structures and the role of these structures in lignin pyrolysis is also addressed. The ways in which elementary deconstruction and repolymerization reactions occur within this structure to form a liquid intermediate and how these deconstruction products continue to interact with each other until they are removed from the liquid intermediate is thoroughly discussed. Further, experimental work with model compounds and the effect of reaction parameters (e.g., temperature, pressure, vapor residence time) are reviewed. Another major challenge to develop microkinetic models of lignin liquefaction is to describe product removal mechanisms (e.g., evaporation, solubilization, thermal ejection) from the liquid intermediate. Group contribution methods are presented for estimation of thermophysical parameters, like normal boiling point and heat of vaporization for model structures. Once the products have been removed from the liquid intermediate, they continue reacting in the aerosol droplets, in vapor phase, or in the solvent depending on the liquefaction technology studied. These “secondary reactions” need to be included in realistic microkinetic models. Based on this review, we can state that with careful implementation, high-quality microkinetic models can be developed to simulate thermochemical lignin liquefaction.

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Section: Effect Of Solventsmentioning

confidence: 99%

Section: Effect Of Solventsmentioning

confidence: 99%