Pyrolysis of Red Eucalyptus, Camelina Straw, and Wheat Straw in an Ablative Reactor

Abstract

The purpose of this study is to produce and characterize biomass pyrolysis liquids obtained in an ablative bed reactor at laboratory scale. The feedstocks selected include eucalyptus (Eucalyptus tereticornis) chips, camelina (Camelina sativa) straw pellets, and wheat (Triticum aestivum) straw pellets. Pyrolysis experiments were carried out at 550 °C and atmospheric pressure with a nitrogen flow rate of 2.24 N L/min and an average solids feeding rate of 2.5 g/min, yielding 42.4, 48.8, and 41.0 wt % liquids for eucalyptus, camelina straw pellets, and wheat straw pellets, respectively. Such liquids, also known as bio-oils, were characterized using gas chromatography−mass spectrometry and complemented with water content, pH measurements, higher heating values, viscosity, and proximate, and ultimate analyses. The distribution of products and their properties were influenced by both the raw materials characteristics (chemical composition and structure) and the operating conditions used in the experimental setup. With regard to raw material characteristics, features such as fixed carbon content in raw biomass seemed to impact the amount of solid products obtained as in the case of eucalyptus chips, which was the sample with higher fixed carbon content and the one that yielded a greater amount of solids. On the other hand, the experimental setup conditioned the results in the sense of how devolatilization of the materials took place, which in turn influenced the yield to liquid products obtained from the process. Wheat straw yielded a bio-oil with a significant number of unknown molecules in the organic phase (∼32.8 wt %), most likely produced from the protein fraction of this biomass. On the other hand, eucalyptus resulted in a larger fraction of carbonaceous residues (∼37.1 wt %), while wheat and camelina straw produced around 28.1 and 25.5 wt %, respectively. Finally, camelina presented interesting characteristics as feedstock for pyrolysis due to its low nitrogen content (0.4−0.5 wt %) and lower char yields (∼25.5 wt %).

Fast pyrolysis of eucalyptus waste in a conical spouted bed reactor

“…At this temperature the yields and concentrations of both components are similar, given that CO formation is enhanced at high temperatures (above 600°C) due to secondary cracking reactions, whereas CO 2 is mainly formed by the primary decomposition of cellulose and hemicellulose at lower temperatures. Similar gas compositions were obtained in eucalyptus pyrolysis studies carried out in other fast pyrolysis reactors (Garcia-Perez et al, 2008;Gomez-Monedero et al, 2015;Heidari et al, 2014;Joubert et al, 2015).…”

“…Thus, Chang et al (2013) and Kim et al (2013), operating in fluidized beds, identified similar compounds, as are phenols, cyclopentanones, acetic acid, furans and levoglucosan, although the concentration of the latter was higher in their studies than in this one, probably due to the avoidance of secondary cracking reactions usually promoted by the ash in the bark (Patwardhan et al, 2010). Finally, Gomez-Monedero et al (2015) pyrolyzed red eucalyptus in an ablative reactor and obtained two fractions, aqueous and organic, with the latter being rich in phenols and the former in acids, ketones, furanes and alcohols.…”

Comparison of Kinetics and Activity of Ni‐Based Catalysts for Benzyl Phenyl Ether Catalytic Hydrogenolysis

“…Currently, this compound is an important basic organic synthetic raw material in the chemical industry and is widely used in plastics, synthetic fibers, pharmaceuticals, pesticides, and dye intermediates . However, because of the structural complexity and variability of lignite, lignite‐related model compounds are widely studied to disclose the mechanisms for lignite depolymerization into small molecules . Such processes usually use heterogeneous catalysts based on either noble or non‐noble metals.…”

Cobalt Nanoparticles Embedded in N‐Doped Porous Carbon Derived from Bimetallic Zeolitic Imidazolate Frameworks for One‐Pot Selective Oxidative Depolymerization of Lignin

“…A series of substituted β ‐O‐4 linkage models were high selectively converted to phenol in moderate to excellent yields (Table , entries 1–6), while previous studies on the oxidative cracking of lignin showed that the yield of phenol was low since phenol was easily oxidized ,. The α ‐O‐4 is another common type of linkage in lignin that has a higher bond energy than the β ‐O‐4 linkage, so breaking α ‐O‐4 linkage has been always a difficult challenge. To our delight, the 8 % conversion rate of α ‐O‐4 linkage could be achieved in the presence of Co@CN (Table , entry 7).…”