• Energy Research

Catalytic fast pyrolysis of biomass offers an opportunity for upgrading of pyrolysis bio-oils using mono- and bimetallic-supported catalysts, which have been demonstrated to improve the bio-oil qua...

Blast Furnace Slag (BFS) is a by-product of the iron ore processing industry with potential to be used in different industrial applications. In this research, BFS was used to examine its ability for dye removal from wastewater. The efficiency of two types of BFS samples for removal of cationic methylene blue (MB) and acidic methyl orange (MO) dyes was investigated and results found that the optimal conditions for treatment of wastewater were 80 g/L of adsorbent dose and 1 h of treatment time for both dyes. BFS was found to be more effective for removal of the acidic MO dye than the cationic MB dye. Under shorter residence times, the results showed reverse trends with BFS samples removing higher concentrations of MB than MO. The BFS chemistry had additional impacts on the efficiency of dye removal. Higher basicity of BFS had lower dye removal ability for adsorption of acidic dye when applied at smaller concentrations, while for cationic dye when applied at higher concentrations. The results showed that BFS has potential role for pre-treatment of industrial wastewater contaminated with dyes and may contribute to reduced use of more expensive adsorbents, such as activated carbons.

Abstract Increasing global energy demand and concerns of carbon emissions have driven the utilisation of renewable sources such as biomass. Biomass pyrolysis in the presence of catalyst, i.e., biomass catalytic pyrolysis (CP), is one of the most efficient routes for generating renewable hydrocarbon fuels or commodity chemicals. Most previous review papers on biomass CP focused on the summary of catalyst classification, properties and performance based on product yields and oil quality. Information on biomass CP process especially effects of different reaction atmospheres has not been reviewed or discussed in sufficient detail. This paper aims to provide a review and insights of the essential process factors and system structure of the lignocellulosic biomass CP with emphasis on process performance indexes such as bio-oil’s effective hydrogen to carbon ratio, deoxygenation degree, carbon efficiency and energy efficiency. The paper sections are organised in order of biomass CP catalysts, biomasss CP assessment, modification of essential process factors (e.g., biomass pre-treatment, co-feeding with other materials, atmosphere and temperature) and variations in the system structure (e.g., heat source alternatives, staged catalysis and process integration). Variations in process factors and system structure can possibly tailor the products and improve the economic attraction. A number of questions about biomass CP are still unclear. The current status, challenges and future research directions of biomass CP are also discussed in the paper. The comprehensive review and insights of the biomass CP process in this work will provide reference for the research and industrialisation of biomass CP for renewable fuel production.

Abstract The aim of this study is to evaluate the suitability of pollutant emission data published in the national pollutant inventories for impact assessment of thermal power generation using Australian technologies as case studies. ReCiPe midpoint and endpoint hierarchist methods were used to investigate the environmental impacts of power stations fuelled with hard coal, brown coal, diesel, coal seam methane, natural gas, landfill gas, sewage gas and bagasse. Brown coal was found to be the most impactful fuel source, followed by hard coal and diesel fuel, all averaging above the Australian national power generation environmental impacts. The renewable energy fuels, bagasse, landfill gas and sewage gas, exhibited the lowest environmental impacts. Global warming and fine particulate matter formation were the two most impactful contributors ranging between 97 and 99.8% of the human health endpoint impacts, while global warming and terrestrial acidification were the most impactful categories to ecosystems contributing between 98.3 and 100% of the ecosystem endpoint impacts. Global warming impacts on human health and ecosystems were the major impactful categories for all fossil fuels, while fine particulate matter formation and terrestrial acidification contributed with the largest respective impacts on human health and ecosystems by the considered renewable energy technologies. The major identified pollutants of concern for the thermal power generation technologies are emissions of greenhouse gases, acidic gases, such as SO2 and NOx, and PM2.5. As an interim solution, reduction in the impacts from the fossil fuel technologies can be achieved by targeting the reduction of the greenhouse gas emissions, better control of acidic gases SO2 and NOx, and blending of the renewable energy sources bagasse, landfill gas and sewage gas with coal and natural gas, however long term solutions would require further reduction in fossil fuel reliance for Australia.

Abstract In this paper, fundamental mechanisms for iron ore reduction in coal–ore mixtures have been investigated using several advanced experimental techniques. Firstly, the thermal properties of coal–ore mixtures were studied and apparent specific heat of coal–ore mixtures against temperature was obtained at a heating rate of 10 °C/min. Several exothermic and endothermic peaks were observed which were related to the decomposition reactions and reduction. The flue gases from the mixture were analysed using a mass spectrometer. Secondly, the X-ray diffraction (XRD) and the iron phase analytical techniques were applied to identify the iron phase changes with the temperature. It has been found that coal devolatilisation and iron oxides reduction occur simultaneously during the heating of the mixture. H2 and CO gases produced from coal devolatilisation and char gasification were responsible for the reduction of iron oxides at these temperatures. Iron oxides undergo step-wise reduction over the whole process. The results in this work provide a fundamental understanding for the direct reduced ironmaking processes.

Pyrolysis of biomass is a means to industrially manufacture renewable oil and gas, in addition to biochar for soil amendment and long-term carbon fixation. In this work, oil and char derived from the slow pyrolysis of the unicellular marine diatom Tetraselmis chui are analysed using a variety of techniques. The pyrolytic oil fraction exhibits a wide variety of fatty acids, alkanes, alkenes, amides, aldehydes, terpenes, pyrrolidinines, phytol and phenols, with a high heating value (HHV) of 28 MJ/kg. The biochar produced has a HHV of 14.5 MJ/kg and reveals a number of properties that are potentially valuable from an agronomic point of view, including high cation exchange capacity (CEC), large concentration of N, and a low C:N ratio. The quantity of C in T. chui biochar that can be expected to stabilise in soil amounts to approximately 9%/wt of the original feedstock, leading to a potential net reduction in atmospheric CO(2).

The products of a commercial one-stage anaerobic digestion and a laboratory-scale pyrolysis of raw food waste (RFW) and digestated food waste (DFW) were characterized to evaluate the treatment effect, product yield, and physicochemical properties. The pyrolysis of the RFW and DFW resulted in generation of 7.4 and 5.3 wt % of gas and 60.3 and 52.2 wt % of bio-oil, while biochar yields decreased with an increase in the pyrolysis temperature. Differential thermogravimetric tests of RFW and DFW show 20% in both solid residues produced at a temperature of 550 °C, indicating a relatively low impact of the digestion process on the RFW. The mineral matter content was found to be lower for RFW compared to DFW. The variation in the content of fixed carbon and volatile matter reflected the effect of anaerobic degradation of the food waste. The bio-oils showed a low concentration of phenols, esters, and derivatives of hydrocarbons for DFW compared to RFW. The specific heat capacities were determined for RFW and DFW, ...

Abstract Pyrolysis is one of the significant technologies that can utilize lignocellulose biomass to produce different bioenergy fuels, such as bio-oil, pyrolytic gases and bio-char. The application of pyrolysis has been extensively studied to produce bio-oil, which is foreseen as the potential transportation fuel in the near future. However, the presence of oxygenated compounds, such as phenols and alcohols in bio-oil makes it highly acidic and unstable for a suitable transportation fuel. These oxygenated compounds can be converted to refinable hydrocarbons by using different catalysts. Therefore, this study aimed to prepare a catalyst that is Cu10%-zeolite and investigated its deoxygenation activity for bio-oil produced from pyrolysis of pine wood sawdust. The catalyst was prepared by a wet-impregnation method. Subsequently, the catalyst was characterized by X-ray diffraction and transmission electron microscopy. Furthermore, the catalyst was applied for in-situ (catalyst: biomass=5) and ex-situ catalytic pyrolysis (catalyst: biomass=3) and the results were compared with those from sole zeolite support. The pyrolysis process was carried out at a heating rate of 100 °C/min to a final temperature of 700 °C and the composition of bio-oil was examined by gas chromatography-mass spectroscopy. The results revealed that Cu-zeolite showed significant deoxygenation activity for bio-oil as compared to zeolite or without any catalyst. Evidently, Cu-zeolite after in-situ pyrolysis produced bio-oil with 20.9% aromatic hydrocarbons and 7.5% aliphatic hydrocarbons, which were approximately 80% and several times higher than with only zeolite, respectively. Meanwhile the concentration of alcohols was reduced from 47.5% to 5%. On the other hand, bio-oil produced from ex-situ catalytic pyrolysis was enriched with 41.6% aromatic hydrocarbons while only 1% alcohols were present in bio-oil. This promising deoxygenation activity can be ascribed to Cu-zeolite’s catalytic activity that converted phenol and alcohols to refinable hydrocarbons via various reactions, such as dehydration, decarboxylation and decarbonylation.