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Review Article: Al-Afif 25
Hydrothermal process liquifaction have lucrative applications (i.e.
Energy-denser product is derived from biomass fertilizer). Possible future research areas
via hydrothemal conversion.As the technology include setting up a plant suitable for both wet
operates in an aques environment, no pre- and dry feedstock, analyzing the influence of
drying of the feedstock is necessery and various parameters, optimizing for better
biomass with higher moisture content can be conversion, and developing theoretical models
directly utilized (22) . HTC yields solid fuel to accurately represent the process depending
(hydrochar) under temperatures between 180– on the feedstock (26) . Moreover, When biomass
280 for 5–240 min (23) . From 250°C to 375°C and is heated to high temperatures during
pressure of 10–25 MPa HTL takes place hydrothermal liquefaction above 375°C the
producing bio-crude or crude-oil,which is a process is known as HTG, macromolecules are
liquid fuel consisting of insoluable organics broken down into molecules with smaller
(24,25) . Bio-crude requires only slight upgrading molecular weights, creating syngas see Fig.2.
to be used commercially while by-products of
Fig.2 Hydrothermal process
Torrefaction handle and transport to locations where it can
Torrefaction is a thermal conversion process be applied for heating fuel, cofiring,
used to pre-treat biomass converting it into a gassification, etc. Optimisation of this
more uniform and energy dense product. technology is expected around combustor,
Heating under inert atmosphere in the
temperature range of 200-300°C enhances the heat exhangers, as well as nitrogen feed, while
fuel properties of biomass by improving research is being conducted on techno-
(7)
combustion properties (27) , homogenuity, economical performance of the technology .
physical and chemical properties making it
Pyrolysis
similar to coal.The torrefied biomass is
For the waste reduction of biomass conversion
biologically stable, hydrophobic, and technologies entire carbon content of the
significantly lower in moisture content feedstock should be converted into a valuable
compared to raw feedstocks (28) . It is expected
product (29) . Pyrolysis distributes carbon atoms
that all traditional pelletisation facilities would between biocrude, char, and syngas (30) . Despite
transition to torreaction plants for the
major success of recent engineering endovours
production of torrefied pellets. Furthermore, on this topic (31) , further research should be
the biomass pre-treated like this is easier to
conducated on novel reactors with improved
SJSI – 2023: VOLUME 1-1
