Process development for biomass delignification using a deep eutectic solvent

Dion Smink

Research output: ThesisPhD Thesis - Research UT, graduation UT

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Lignocellulosic biomass is the most abundantly available sustainable raw material on earth. Replacing fossil feedstocks for the chemical industry, such as oil, coal and natural gas by biomass can reduce the CO2 emissions of the chemical industry. However, the availability of lignocellulosic biomass is limited. Therefore, it is key to use this feedstock as efficiently as possible. The current benchmark process in biomass fractionation is the kraft process. In this process, biomass is delignified using a solution of sodium hydroxide and sodium sulfide and the produced cellulose pulp is mostly used for papermaking. However, only half of the raw material is converted into cellulose pulp, the rest of the material is combusted for the generation of heat and for the recovery of sodium sulfide. Processes that can convert biomass in multiple products, including next to cellulose, also lignin and/or furans, are required to reduce global CO2 emissions.

Deep eutectic solvents (DES) are composite solvents that exhibit deep eutectic behavior upon mixing. These solvents have shown great potential for biomass delignification and
have the potential to produce not only cellulose pulp, but also other valuable byproducts, such as lignin and furans. Therefore, DES based processes can make more efficient use of the biomass feedstock than the kraft process. However, there are a couple of issues that need to be resolved before DES delignification processes can be applied on a large scale. First, the advantages of the combination of DES constituents are poorly understood. Second, the known methods for the recovery of lignin from DES are mostly applicable for laboratory purposes. Laboratory unit operations are not always applicable on industrial scale, and research is needed to better understand the pulping process, as well as solvent recovery operations. These issues are addressed in this thesis, after which a conceptual process is designed for the delignification of Eucalyptus globulus using a DES comprised of lactic acid and choline chloride.

Original promotion date was July 3, 2020 (COVID-19)
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • University of Twente
  • Schuur, Boelo, Supervisor
  • Kersten, Sascha R.A., Supervisor
Award date16 Dec 2020
Place of PublicationEnschede
Print ISBNs978-90-365-5029-1
Publication statusPublished - 16 Dec 2020


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