Methacrylated lignin was reacted with PH
(g) to prepare a phosphorus rich bio-based polymer containing PH/PH
functional groups, which were converted to tertiary phosphine units via the phosphane-ene ...reaction. This represents a straightforward method for the upconversion of low-value biomass waste to useful inorganic polymer with potential utility in metal scavenging applications.
In this study bio-based bio-phenol-formaldehyde (BPF) resoles were prepared using hydrolytically depolymerized Kraft lignin (DKL) as bio-phenol to partially substitute phenol. The effects of phenol ...substitution ratio, weight-average molecular weight (
) of DKL and formaldehyde-to-phenol (F/P) ratio were also investigated to find the optimum curing temperature for BPF resoles. The results indicated that DKL with
~ 1200 g/mol provides a curing temperature of less than 180 °C for any substitution level, provided that F/P ratios are controlled. Incorporation of lignin reduced the curing temperature of the resin, however, higher
DKL negatively affected the curing process. For any level of lignin
, the curing temperature was found to increase with lower F/P ratios at lower phenol substitution levels. At 25% and 50% phenol substitution, increasing the F/P ratio allows for synthesis of resoles with lower curing temperatures. Increasing the phenol substitution from 50% to 75% allows for a broader range of lignin
to attain low curing temperatures.
► Ru modified Ni/γ-Al2O3 catalyst was effective in catalyzing biomass SCWG for H2 production. ► H2 yield increased with increasing reaction temperature, but decreased with increasing WHSV. ► ...Activated carbon as a catalyst support was more resistant than γ-Al2O3 to alkali attack in SCW. ► Biomass ashes not only catalyzed SCWG reactions but also resulted in reactor plugging. ► Hydrothermal liquefaction combined with SCWG was an effective approach for sludge treatment.
Supercritical water gasification (SCWG) of glucose solution (50–200g/L), a simulated aqueous organic waste (composed of glucose, acetic acid and guaiacol) and a real aqueous organic waste stream generated from a sludge hydrothermal liquefaction process was performed in a bench-scale continuous down-flow tubular reactor with novel 0.1RuNi/γ-Al2O3 or 0.1RuNi/activated carbon (AC) catalyst (10wt.% Ni with a Ru-to-Ni molar ratio of 0.1). 0.1RuNi/γ-Al2O3 was very effective in catalyzing SCWG of glucose solution and the simulated aqueous organic waste, attaining an H2 yield of 53.9mol/kg dried feedstock at 750°C, 24MPa and a WHSV of 6h−1. However, the γ-Al2O3-supported catalyst was not resistant to the attack of alkali and nitrogen compounds in the real waste during the SCWG of the real aqueous organic waste, whereas the AC-based catalyst exhibited higher stability. This research provides a promising approach to the treatment and valorization of aqueous organic waste via SCWG.
The activities of various supported catalysts were tested in a continuous flow reactor for production of CH4 and H2 from glucose via supercritical water gasification (SCWG) at a relatively low ...temperature (500°C). Based on this preliminary study, among all catalysts tested in this study Ni20%Ru2%/γ-Al2O3 catalyst was found to be the most active, achieving complete conversion of all carbon in glucose at 500°C and a weight-hourly space velocity (WHSV) of 3h−1. The addition of 2% Ru to Ni20%/γ-Al2O3 not only suppressed char/tar formation, promoted the carbon gasification efficiently, but also increased methane formation. Moreover, high stability of Ni20%Ru2%/γ-Al2O3 catalyst was demonstrated in the experimental runs for 20h on-stream. The roles of ruthenium as a co-catalyst in Ni/Al2O3 were found to be not only increasing nickel dispersion, enhancing nickel's reducibility, but also preventing leaching of Al and Ni metals in SCW. However, NiRu supported on either TiO2 and activated carbon led to lower catalytic activity and frequent plugging after only 3h on-stream.
•Renewable CH4/H2 efficiently produced by SCWG of glucose at 500°C.•Ni20%Ru2%/Al2O3 exhibited the highest activity/stability for CH4 yield.•Ru proved to be an excellent promoter to Ni catalyst for SCWG of biomass.•Ru promotes Ni catalysts by enhancing dispersion/reducibility of metals.
The global steel production has been growing for the last 50 years, from 200 Mt in 1950s to 1 240 Mt in 2006. Iron and steel making industry is one of the most energy-intensive industries, with an ...annual energy consumption of about 24 EJ, 5% of the world＇s total energy consumption. The steel industry accounts for 3%-4% of totat world greenhouse gas emissions. Enhancing energy efficiency and employing energy saving/recovering technologies such as coke dry quechning （CDQ） and top pressure recovery turbine （TRT） can be short-term approaches to the steel industry to reduce greenhouse gas emission. The long-term approaches to achieving a significant reduction in CO2 emissions from the steel industry would be through developing and applying CO2 breakthrough technologies for iron and steel making, and：through increasing use of renewable energy for iron and steel making. Thus, an overview of new CO2 breakthrough technologies for iron and steel making was made.
•Low-lipid microalgae was converted into bio-crude oil.•Methanol was identified as the most effective reaction medium for liquefaction.•The highest oil yield of 85.5 wt% was obtained at 225 °C for ...1 h in methanol.
This study aimed to determine the most effective reaction medium for producing bio-crude oil from low-lipid microalgae via liquefaction treatment. To this end, the screening tests were carried out at 275 °C for 60 min by employing varying reaction media including water, water with four acid catalysts (formic acid, acetic acid, sulfuric acid, and hydrochloride acid), and four different organic solvents (methanol, ethanol, ethyl acetate, and acetone) without acid catalyst. In view of the bio-crude oil yield, methanol as the most effective reaction medium was choses for the further investigation on the effects of residence time, biomass/solvent mass ratio, and reaction temperature on the products distribution. The results showed that liquefaction at 225 °C for 60 min with a 1:5 biomass/solvent mass ratio led to the highest bio-crude oil yield of 85.5 wt% and a higher heating value (HHV) of 30.6 MJ/kg. Finally, a series of analytical approaches (elemental, GPC, TGA, GC–MS, and FT-IR analysis) were conducted for characterizing bio-crude oil.
In recent studies, various reports reveal that stubble burning of crop residues in India generates nearly 150 million tons of carbon dioxide (CO2), more than 9 million tons of carbon monoxide (CO), a ...quarter-million tons of sulphur oxides (SOX), 1 million tons of particulate matter and more than half a million tons of black carbon. These contribute directly to environmental pollution, as well as the haze in the Indian capital, New Delhi, and the diminishing glaciers of the Himalayas. Although stubble burning crop residue is a crime under Section 188 of the Indian Penal Code (IPC) and the Air and Pollution Control Act (APCA) of 1981, a lack of implementation of these government acts has been witnessed across the country. Instead of burning, crop residues can be utilized in various alternative ways, including use as cattle feed, compost with manure, rural roofing, bioenergy, beverage production, packaging materials, wood, paper, and bioethanol, etc. This review article aims to present the current status of stubble-burning practices for disposal of crop residues in India and discuss several alternative methods for valorization of crop residues. Overall, this review article offers a solid understanding of the negative impacts of mismanagement of the crop residues via stubble burning in India and the other more promising management approaches including use for bioenergy, which, if widely employed, could not only reduce the environmental impacts of crop residue management, but generate additional value for the agricultural sector globally.
The growing demand for petroleum, accompanied by the declining petroleum reserves and the concerns over energy security, has intensified the interest in direct coal liquefaction (DCL), particularly ...in countries such as China which is rich in coal resources, but short of petroleum. In addition to a general introduction on the mechanisms and processes of DCL, this paper overviews some recent advances in DCL technology with respect to the influencing factors for DCL reactions (temperature, solvent, pressure, atmospheres, etc.), the effects of coal pre-treatments for DCL (swelling, thermal treatment, hydrothermal treatment, etc.), as well as recent development in multi-staged DCL processes, DCL catalysts and co-liquefaction of coal with biomass.
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