Paper details

Title:

Hydrothermal Liquefaction of Black Liquor

Author(s):

Wörner, M., Hornung, U., Dahmen, N.

Document(s):

Abstract:

Black liquor, which is produced in large quantities in the pulp & paper industry as a by-product in the Kraft process is an interesting feedstock for hydrothermal liquefaction (HTL). HTL is a thermochemical process to convert organic matter into biocrude for fuel applications or the production of useful chemical compounds and is especially useful for wet biomass. Main organic matter in Black liquor is lignin which is dissolved in an aqueous solution together with the cooking chemicals from pulping. Desired products in HTL of lignin are aromatic compounds. Until now, most research was done with extracted lignin. This work explores the approach to liquefy the lignin directly in the black liquor via HTL as a part of the “Black Liquor to Fuels (BL2F)” project. In order to investigate the feasibility of direct HTL of black liquor, we performed parameter studies in batch experiments using micro autoclaves. The product phases were separated and analyzed using different analytical methods. Our study shows that the typical depolymerization products of lignin are found dependent on temperatures and residence times. Catechol and its derivates are the aromatic monomer products in the organic phase. The SEC analysis of the biocrude gives a good indication of the depolymerization of the lignin with increasing reaction temperature and holding time. Overall, it can be said that the direct use of black liquor in an HTL process works, which reduces process steps in advance for example extracting the lignin.

Keywords:

biorefinery, lignin, thermochemical conversion, hydrothermal liquefaction

Topic:

Biomass Conversion to Intermediate Bioenergy Carriers and Sustainable Biofuels

Subtopic:

Hydrothermal processing

Event:

30th European Biomass Conference and Exhibition

Session:

5DO.3.2

Pages:

867 - 874

ISBN:

978-88-89407-22-6

Paper DOI:

10.5071/30thEUBCE2022-5DO.3.2

Price:

FREE