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PhD Defense by Kasia Arturi

Kasia Arturi, Department of Chemistry and Bioscience, will defend her thesis on "Value-added Products by Optimization of Solvothermal Liquefaction of Wastes"


11.05.2017 kl. 13.00 - 16.00



"Value-added Products by Optimization of Solvothermal Liquefaction of Wastes"


The need to replace fossil-based fuels, materials, and chemicals has spurred intense research in dozens of biomass conversion fields. Hydrothermal liquefaction (HTL) is a thermochemical technique that utilizes the unique properties of near- and supercritical water to convert complex biomass feeds into a spectrum of value-added products, namely drop-in energy carriers, transportation biofuels, and platform chemicals. The process is versatile in terms of feedstocks and would, therefore, be an excellent addition to a future biorefinery. However, numerous challenges must be overcome before liquefaction can be commercialized.

This thesis deals with the optimization of different liquefaction aspects in order to promote its further advancement, including I ) Application of multivariate analysis for prediction of generally valid trends in process' outputs as a function of reaction conditions; II) Optimization of products' characterization; III) Development of innovative reactors and procedures combining the ease of batch processing with improved parameter control; and IV) Assessment of different types of wastes as a raw feed to liquefaction and a source of value-added products.  The results showed that biomass characteristics are the most important factors influencing the HTL output and that each biomass type requires a different set of optimized process parameters. Furthermore, the quality and the statistical significance of the models varied notably dependent on the biomass type and the response.

The characterization of the liquefaction products was improved significantly by application of advanced analytical tools and methods, including solid-phase microextraction (SPME) and high-resolution liquid chromatography mass spectrometry (LC-ESI-MS/MS).  Utilization of such techniques was shown to be crucial for an accurate quantification of the produced chemicals. A strict control of the liquefaction process parameters is an absolute prerequisite for obtaining results comparable to continuous systems and commercialization of the technology. Application of cold injection of biomass into a preheated and pre-pressurized reaction medium was a procedure combining fast heating rates with precise residence time control. Also, the applied pressure regulation system adapted the reaction medium density, increasing the control over conversion pathways. Liquefaction of wastes resulted in a broad spectrum of products, mainly biofuels and biochemicals, depending on the feedstock.

The most promising outputs from HTL of lignin included aromatic monomers, which could replace the fossil resources as platform chemicals. In addition to the aromatics, liquefaction of lignocellulosic biomass also yielded cyclic compounds, which can be utilized as high-value building blocks and precursors for drugs, fragrances, and fuels. Conversion of an unsaturated polyester resin resulted in the recovery of monomers from the polymer chains, in addition to the high-value secondary reaction products.


  • Professor MSO, Erik Gydesen Søgaard, Department of Chemistry and Bioscience, Aalborg University, Denmark


  • Professor, Shuguang Deng, School for Engineering of Matter, Transport and Energy, Arizona State University, USA
  • Professor Peter Westh, Department of Science and Environment, Roskilde University, Denmark
  • Associate Professor, Donghong Yu, Department of Chemistry and Bioscience, Aalborg University, Denmark





Department of Chemistry and Bioscience, Section of Chemical Engineering


Niels Bohrs Vej 8, 6700 Esbjerg, room: C1.119

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