Lignocellulosic biomass pyrolysis mechanism: A state-of-the-art review

Pyrolysis is one of the thermochemical technologies for converting biomass into energy and chemical products consisting of liquid bio-oil, solid biochar, and pyrolytic gas. Depending on the heating rate and residence time, biomass pyrolysis can be divided into three main categories slow (conventional), fast and flash pyrolysis mainly aiming at maximising either the bio-oil or biochar yields. Synthesis gas or hydrogen-rich gas can also be the target of biomass pyrolysis. Maximised gas rates can be achieved through the catalytic pyrolysis process, which is now increasingly being developed. Biomass pyrolysis generally follows a three-step mechanism comprising of dehydration, primary and secondary reactions. Dehydrogenation, depolymerisation, and fragmentation are the main competitive reactions during the primary decomposition of biomass. A number of parameters affect the biomass pyrolysis process, yields and properties of products. These include the biomass type, biomass pretreatment (physical, chemical, and biological), reaction atmosphere, temperature, heating rate and vapour residence time. This manuscript gives a general summary of the properties of the pyrolytic products and their analysis methods. Also provided are a review of the parameters that affect biomass pyrolysis and a summary of the state of industrial pyrolysis technologies.

Lignocellulosic biomass pyrolysis: A review of product properties and effects of pyrolysis parameters

Spinels with the formula of AB2O4 (where A and B are metal ions) and the properties of magnetism, optics, electricity, and catalysis have taken significant roles in applications of data storage, biotechnology, electronics, laser, sensor, conversion reaction, and energy storage/conversion, which largely depend on their precise structures and compositions. In this review, various spinels with controlled preparations and their applications in oxygen reduction/evolution reaction (ORR/OER) and beyond are summarized. First, the composition and structure of spinels are introduced. Then, recent advances in the preparation of spinels with solid-, solution-, and vapor-phase methods are summarized, and new methods are particularly highlighted. The physicochemical characteristics of spinels such as their compositions, structures, morphologies, defects, and substrates have been rationally regulated through various approaches. This regulation can yield spinels with improved ORR/OER catalytic activities, which can furth...

Spinels: Controlled Preparation, Oxygen Reduction/Evolution Reaction Application, and Beyond

Alternative Monomers Based on Lignocellulose and Their Use for Polymer Production.

Biomass feedstocks for renewable fuel production: a review of the impacts of feedstock and pretreatment on the yield and product distribution of fast pyrolysis bio-oils and vapors

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Effect of torrefaction on structure and fast pyrolysis behavior of corncobs

Perovskite-type oxides LaFe1−xCoxO3 for chemical looping steam methane reforming to syngas and hydrogen co-production

Two-staged biomass pyrolysis process consisting of torrefaction and subsequent fast pyrolysis is proposed to obtain high quality bio-oil. The purpose of this study is to evaluate the effect of torrefaction temperature on yield, composition, and physical properties of the liquid of torrefaction and bio-oil. Torrefaction of pine was conducted on an auger reactor at 240–320 °C with a residence time of 40 min to produce liquid of torrefaction and torrefied pine. Then, the torrefied pine was fast pyrolyzed in a bubbling fluidized bed reactor at 520 °C to produce bio-oil. Torrefied pine was characterized by chemical composition analysis and Fourier transform infrared (FTIR) spectroscopy. The liquid of torrefaction was determined by gas chromatography (GC); bio-oil was characterized by gas chromatography mass spectroscopy (GC-MS) and 13C nuclear magnetic resonance spectrometry (NMR). The experimental results show that water content in liquid of torrefaction and water and acetic acid content in bio-oil decreased ...

Effect of Torrefaction Temperature on Product Distribution from Two-Staged Pyrolysis of Biomass

To determine the effect of crystal sizes of ZSM-5 and feedstock species on aromatic yield and selectivity from catalytic fast pyrolysis of biomass, catalytic fast pyrolysis (CFP) of different feedstock species (cellulose, hemicellulose, lignin, pine, corncob and straw) over ZSM-5 with varying crystal size (2 μm, 200 nm and 50 nm) was conducted in a Pyroprobe pyrolyzer (5200, CDS Analytical). The experimental results show that ZSM-5 with crystal size of 200 nm exhibited the maximum aromatic yield and minimum BTX selectivity. The results could be attributed to its highest micropore surface area, amount of weak acid and maximum Bronsted to Lewis acid sites ratio (B/L ratio). Cellulose, hemicellulose and lignin play very different roles in catalytic fast pyrolysis of biomass. Cellulose exhibited the maximum aromatic yield of 38.4% and minimum non-condensable gas yield of 18.4%. Lignin showed the highest coke yield of 68.6% and lowest aromatic yield of 10.2%. And hemicellulose displayed the lowest coke yield of 29.4% and highest yield of non-condensable gas of 39.1%.

Effect of crystal size of ZSM-5 on the aromatic yield and selectivity from catalytic fast pyrolysis of biomass

To understand the effect of torrefaction severity on structure changes of hemicellulose, cellulose, lignin and their subsequent catalytic fast pyrolysis (CFP) behavior, torrefaction of lignin, hemicellulose, and cellulose was performed in a tubular reactor with different reaction temperatures (210–300 °C) and residence times (20–60 min). The experimental results show that the rank order of thermal stability during torrefaction was cellulose > lignin > hemicellulose. The torrefied hemicelulose, cellulose, and lignin were subsequently catalytic-fast-pyrolyzed over HZSM-5 in a semi-batch pyroprobe reactor. The effects of the torrefaction temperature and residence time on aromatic yields and selectivity from CFP of torrefied hemicellulose, cellulose, and lignin were investigated. The experimental results showed that torrefaction can cause the reduction in the aromatic yield and increase in benzene, toluene, and xylenes (BTX) selectivity from CFP of torrefied hemicellulose and lignin. It has little impact on C...

Anqing Zheng

Papers

Effect of torrefaction on structure and fast pyrolysis behavior of corncobs

Perovskite-type oxides LaFe1−xCoxO3 for chemical looping steam methane reforming to syngas and hydrogen co-production

Effect of Torrefaction Temperature on Product Distribution from Two-Staged Pyrolysis of Biomass

Effect of crystal size of ZSM-5 on the aromatic yield and selectivity from catalytic fast pyrolysis of biomass

Impact of Torrefaction on the Chemical Structure and Catalytic Fast Pyrolysis Behavior of Hemicellulose, Lignin, and Cellulose