Characteristic studies on the biochars produced by hydro-thermal and steam gasification of canola hull and canola meal fuel pellets

Biochars, based on their production process and biomass precursor, can have a broad range of structural, compositional, chemical, and physical properties. These properties are important for identifying the biochar performance and stability in further applications. Non-food biomass has a great potential to produce biochars. Two inherent agricultural biomasses from Canadian prairies including canola hull and canola meal were used for the production of fuel pellets. This study provides information on the specific features of biochars produced by steam and hydro-thermal gasification of these fuel pellets compared with those of well-known pyrolysis biochars. For steam gasification, the steam to biomass ratio (SBR=0.31, 0.47, and 0.62) and gasification temperature (T=650, 750 and 850 oC) were used as the main process parameters. In contrast, for hydro-thermal (supercritical water) gasification, the effects of gasification temperature (T= 350, 450, 550, and 650 oC) were studied on the biochar properties at a constant pressure, feed concentration and reaction time. Different characterization techniques were used to study the physical, chemical, and structural characteristics of biochar products. Characterization results, for steam-gasified biochars confirmed development of aromatic carbon structure and formation of composite char. XRD spectra for biochars produced through steam gasification showed no retention of biochemical features from the parent precursors in the biochars prepared in different levels of operating conditions. FTIR spectra confirmed the rearrangement of biomass structure at the early stages of steam gasification for all used operating conditions. Elemental analysis and Van Krevelen plot showed that for pellets, the H/C and O/C atomic ratios were in the range of biomass material. However, after gasification, the these atomic ratios for biochars were in the range of them for coal material, especially lignite coal. SEM analysis showed that steam-gasified biochars had much more cracked surface as compared with hydro-thermally prepared biochars. This observation was consistent with the results of porous characteristics for biochars which showed low BET surface area (\u3c11 \u3em2/g) for hydro-thermally produced biochars but it was much larger (\u3e 400 m2/g) for steam-gasified biochars. XRD results for hydro-thermally prepared biochars at 350 oC showed the presence of cellulose I and cellulose II in the material structure, but the related peaks were not observed for the biochar prepared at hydro-thermal gasification temperature of 650 oC. For prepared biochars prepared at the highest temperature of hydro-thermal gasification, Raman analysis showed a large change in ID/IG ratio compared with that for biochar prepared at temperature of 350 oC confirming a drastic structural change in biochar structure. Results from other characterization techniques such as XRD, ICP-MS, and thermogravimetric analysis will be also discussed in the presentation. The degradation of biochars was progressive with the rise in hydro-thermal gasification temperature from 350 to 650°C. Hydro-thermally produced biochars showed characteristics of transition char at low temperature (350 oC as gasification temperature) and properties of amorphous char at high temperature (≥550 oC). For steam-gasified biochars, higher BET surface area indicated the development of composite char. It is noteworthy that characterization results showed that the steam-gasified biochars did not have the compact aromatic structure of turbostratic char and their aromatic structure is not developed as biochars produced via pyrolysis. However, properties of steam-gasified biochars showed their great potential for industrial applications such as adsorptive and/or catalytic applications. In addition, both types of biochars due to their mineral contents can be tested for agricultural applications(soil amendment and productivity)

Characteristic studies on the waste biomass-based biochars produced by fast pyrolysis

Biochar, as carbonaceous product obtained from pyrolysis of biomass, has many applications in diverse areas due to its versatile physicochemical properties. Non-food biomass has a great potential to produce biochars. In the present study, pinewood sawdust (forest residue), wheat straw and flax straw (agricultural residues), and poultry litter (livestock manure) were used as precursors for pyrolysis. Focus of this study was on the effects of fast pyrolysis temperature (400, 475, and 550 oC) on the characteristics of biochars produced by means of a mobile pyrolysis unit. Different characterization techniques are used to study the physical, chemical, and structural characteristics of biochar products. Please click on the file below for full content of the abstract

A Novel Approach Towards Waste Treatment in FBC

Abstract Waste combustion has the potential to play an important role in the energy production despite its contribution to heavy metals emissions. A new multi-zone temperature combustion technique, known as a Low-High-Low (LHL) temperature method, was developed to reduce pollutant emissions, particularly heavy metals, from FBCs. This paper focuses on the environmental impacts of biowaste combustion at different FBC conditions with emphasis on gas and solid emissions. The biowaste (de-inking sludge) studied contained 15% moisture, 27% carbon, 18% oxygen, and 35% ash. Ash elemental analysis shows a dominance of SiO 2 , Al 2 O 3 and CaO (38%, 28% and 19%, respectively) with selected alkalis Na 2 O and K 2 O (0.3% and 0.2%, respectively). The used biowaste material had a heating value of 10,000 kJ/kg, which indicates that its combustion may be used to treat a portion of the total solid waste produced, while generating energy. The paper reports the following results of LHL vs. Classical FBC: (1) average axial profiles of gas concentrations (NO, NO x , and CO 2 ) as well as their final averages at the exhaust, (2) final heavy metals leachability from generated fly ash. During the multi-temperature combustion experiments (LHL), the final average gas measurements for NO, NO x , and CO 2 were 91 ppm, 175 ppm, and 6.1%, respectively. As for the classical FBC experiments, the final average gas measurements were similar (94 ppm, 141 ppm and 5.9% for NO, NO x and CO 2 , respectively). The final fly ash sample had leachability rates of 0.14 ppm and 0.061 ppm for Cd and Cr, respectively. Such low leachability rates are due to the LHL's ability to form dense and compact final fly ash structures. On the contrary, 30.7 ppm and 14.3 ppm of Cd and Cr leached out of the porous no-LHL final fly ash structures, respectively. These results confirm that the LHL combustion could be considered as an effective waste-to-energy approach

Concluding Remarks

Junasz Kozinski, Dean, Lassonde School of Engineering, York University, delivers some concluding remarks

Concluding Remarks

Junasz Kozinski, Dean, Lassonde School of Engineering, York University, delivers some concluding remarks

Butanol and ethanol production from lignocellulosic feedstock: biomass pretreatment and bioconversion

Lignocellulosic feedstock has tremendous potential to sustain the renewable production of biofuels such as ethanol and butanol. Although lignocellulosic biomass is a storehouse of energy in the form of cellulose and hemicellulose, yet lignin acts as a barrier against their hydrolysis. A dilute acid pretreatment disintegrates the biomass complex and allows cellulolytic enzymes to hydrolyze cellulose and hemicelluloses in releasing fermentable sugars. The current study investigates the effect of different H2SO4 doses (0–2.5%) on the three lignocellulosic feedstock material, especially pinewood, timothy grass, and wheat straw at 121°C for 1 h. Furthermore, the pretreated feedstock was subjected to enzymatic hydrolysis using cellulase, β-glucosidase, and xylanase at 45°C for 72 h. The biomass hydrolysates containing monomeric sugars (glucose and xylose) were fermented using Saccharomyces cerevisiae and Clostridium beijerinckii for ethanol and butanol production, respectively. A comparative evaluation for the concentrations of ethanol and butanol, residual sugars as well as byproducts such as acetone, acetate, and butyrate from biomass hydrolysates was performed. Pinewood hydrolysate revealed high ethanol (24.1 g/L) and butanol (11.6 g/L) concentrations due to greater sugar content. In contrast to ethanol fermentation by S. cerevisiae, butanol fermentation by C. beijerinckii demonstrated low butanol levels in the hydrolysates due to butanol toxicity toward clostridia