Packed-Bed Pyrolysis of Alkali Lignin for Value-Added Products
Year: 2025
Type: article
Abstract: Lignin is the largest renewable source of aromatic biopolymers on Earth, and it is commercially available as by-product of biorefineries and pulp/paper industries. It is mainly burned for heat and power, but pyrolysis can provide high-value-added products. In this study, the pyrolysis characteristics of alkali lignin pellets are investigated using a packed-bed reactor at a laboratory scale for heating temperatures of 800–900 K. Conversion dynamics are analyzed by means of the thermal field and the rates of gaseous species release, which is a very innovative aspect of the study. The yields of the lumped product classes do not vary significantly in the range of heating temperatures examined (biochar yields around 58–63 wt%, together with gas and liquid yields around 9–12 and 28–30 wt%, respectively). Carbon dioxide is the most abundant gaseous product, followed by methane and carbon monoxide (smaller amounts of C2 hydrocarbons and hydrogen), while bio-oil is rich in phenolic compounds, especially guaiacols, cresols, and phenol. A comparison with the conversion dynamics of fir, beech, and straw reveals that, mainly as a consequence of softening and melting, the lignin heat- and mass-transfer rates as well as actual reaction temperatures are profoundly different. In fact, the characteristic process size becomes the diameter of the reactor rather than that of the pellets.
Source: Recycling
Authors: Carmen Branca, Colomba Di Blasi
Institutions: National Research Council, University of Naples Federico II
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,172
OpenAlex ID: W4409332126