Co-pyrolysis of coal and raw/torrefied biomass: a review on chemistry, kinetics and implementation
Date
2021Author
Gouws, S.M.
Bunt, J.R.
Neomagus, H.W.J.P.
Carrier, M.
Metadata
Show full item recordAbstract
Thermochemical conversion via co-pyrolysis has the potential to be an efficient route for converting biomass to
bio-energy and bio-refinery products. In this review, the implementation of co-pyrolysis of torrefied biomass and
coal was critically assessed against co-pyrolysis of raw biomass and coal from both a fundamental and engineering
perspective. This evaluation showed fundamental advantages for torrefaction of biomass prior to copyrolysis
such as a decrease in mass and heat transfer limitations due to an increase in permeability and thermal
conductivity of biomass. Co-pyrolysis volatiles may also be upgraded through the catalytic activity of the
torrefied biomass surface, producing higher quality oil. Due to properties more similar to coal, torrefied biomass
requires less energy for milling (lower operating costs) and can be more easily blended with coal in reactor
feeding systems. A state-of-the-art research on co-pyrolysis kinetics revealed that reactivities of blends may be
predicted from kinetic parameters of individual feedstocks using an additive approach. To conclude on the
preferred reactor design for this process, different reactors were evaluated based on heat transfer mode, operation
and product formation. Although both the fluidized bed and rotating cone reactor provide high oil yields,
the rotating cone has been more successful commercially. This design shows great promise for specifically copyrolysis
due to the intimate contact that may be achieved between fuels to maximize synergy. The copyrolysis
of torrefied biomass and coal may be encouraged from a scientific point of view, however further
research is recommended on the effective integration of torrefaction and co-pyrolysis technologies.
URI
http://hdl.handle.net/10394/35649https://doi.org/10.1016/j.rser.2020.110189
https://www.sciencedirect.com/science/article/pii/S1364032120304792
Collections
- Faculty of Engineering [1129]