Recent Advances in Biomass Energy Torrefaction, Pyrolysis and Gasification Technologies

Dear Colleagues,

Biomass as a feedstock has huge potential to replace fossil fuels and it should reduce greenhouse gas (GHG) emissions by 2050. Today, the world’s main problem is that CO₂ emissions are rising every year, and in 2020, the atmospheric CO₂ concentration was already higher than 410 ppm, which is beyond the safe global limits. This implies that the anthropogenic activity from fossil fuel combustion still plays an important role in energy consumption, even though great efforts have been made to generate power from solar and wind energy. Recently, bioenergy has become the fourth largest primary energy source after oil, coal, and natural gas, and is proven to be very advantageous. Biomass torrefaction is a thermochemical process (carbonization and roasting) that treats biomass at 200–350 ⁰C. It is carried out under atmospheric conditions and in the absence of oxygen. During the process, the water contained in the biomass as well as superfluous volatiles are removed, and the biopolymers (cellulose, hemicellulose and lignin) partly decompose, releasing various types of volatiles (i.e., torrefaction off-gas volatiles).

By using thermochemical conversion of biomass feedstocks, it is possible to upgrade biomass feedstocks through the use of different types of valorization techniques, such as the following:

• Pyrolysis;
• Dry torrefaction (oxidative or non-oxidative conditions);
• Wet torrefaction (water and diluted acid);
• Steam torrefaction;
• Gasification.

The torrefaction process can be categorized and group into dry and wet torrefaction; it can be also divided into oxidative torrefaction and non-oxidative torrefaction. In the last 20 years, a great number of different torrefaction methods have been investigated and developed. Non-oxidative torrefaction, commonly termed torrefaction, has been shown to have a greater potential for commercial applications and industrial applications compared to other methods.

This Special Issue will focus on different biomass torrefaction processes and their applications in low-carbon demand industries for the production of carbonized solid biofuels, biochar as an additive for organize fertilizers, biosorbents’ production for chemical industry, and thermochemical process production. This Special Issue will also address torrefaction process upgrades to obtain new bioproducts for special (functional applications) purposes, for example, activated carbon for deodorization in biogas plants. We therefore invite papers exploring biomass torrefaction process technology, bioproduct production for different industrial applications, torrefaction process kinetics modeling, reviews, industrial demo examples, case study scenarios, and LCA analysis of biomass torrefaction plants. Topics of interest for publication include, but are not limited to, the following:

• Biomass torrefaction technologies;
• Biomass torrefaction modeling: lab-scale, semi-industrial-scale and full-scale scenarios;
• Kinetics of biomass torrefaction processes;
• Techno-economical assessments of biomass torrefaction plants;
• Emission problems related to biomass torrefaction product storage;
• Safety aspects of biomass torrefaction processes in semi-industrial and industrial-scale scenarios;
• Environmental evaluation of biomass torrefaction processes;
• Optimization of biofuel production processes;
• Impacts of raw material processing on product parameters;
• LCA and SLCA analysis of biomass torrefaction plants.

Dr. Szymon Szufa
Guest Editor

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