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Corrugated cardboard (CCB) comprises a substantial portion of municipal solid waste, of which ~5% is wax coated CCB (WCCB) to enhance its performance. WCCB cannot be recycled, making it a suitable resource to recover wax and produce char. The WCCB was characterized for its extractable wax, lignin, and carbohydrate contents and by thermogravimetric analysis to study its thermal degradation behavior. WCCB was preliminarily examined by pyrolysis‐gas chromatography–mass spectrometry to determine product composition. WCCB samples were then pyrolyzed in auger and tube reactors at 450, 500, and 550°C, and their pyrolysis wax‐oil and char products characterized. WCCB and char were subjected to proximate, ultimate, surface area, analyses. The highest char yield was 36% at 450°C, and the highest wax‐oil yield was 53% at 550°C in the tube reactor. The wax‐oil fraction contained mainly alkanes, alkenes, and dienes (C9–C36), and chain length decreased with pyrolysis temperature. This wax fraction could be recovered and used as bunker fuel (C12–C40) or further converted to diesel (C10–C20). [ABSTRACT FROM AUTHOR]

Iron/nanospring (Fe/NS) catalysts with different metal promoters (Co, Mo, Cu, and Ru) were synthesized via the co-impregnation method and employed to investigate effects of these metals on the physico-chemical properties and catalytic behavior of Fe/NS catalyst during the Fischer-Tropsch synthesis (FTS). The prepared catalysts were characterized before the FTS reaction by various techniques, such as BET surface area, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), temperature programmed reduction (H 2 -TPR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA) and thermogravimetric analysis (TGA). The FTS performance of the prompted catalysts was examined in a quartz fixed-bed microreactor (H 2 /CO of 2:1, 230 °C and atmospheric pressure) and the products trapped and analyzed by gas chromatography (GC) and GC-mass spectrometry (GC–MS) to determine CO conversion and reaction selectivity. The characterization results obtained indicated that the promotion of Fe/NS catalyst with Co, Mo, Cu and Ru oxides enhanced the catalytic activity of Fe/NS catalyst. The catalytic performance over Ru-Fe/NS, Co-Fe/NS, Mo-Fe/NS and Cu-Fe/NS catalysts at the same conditions showed that CO conversion was 93.3%, 43.6%, 82.4% and 56.3%, respectively. The C 6 -C 16 liquid hydrocarbon selectivity was 41.1%, 30.1%, 25.4% and 33.8%, respectively. The addition of promoters led to an increase in the selectivity towards olefins instead of aromatics over the non-promoted Fe/NS catalyst. Finally, it was found that the Ru, Co, MO and Cu promoters proved to have a significant effect on selectivity towards desired products namely paraffins and olefins. [ABSTRACT FROM AUTHOR]

A nanostructured iron (Fe) catalyst for Fischer-Tropsch synthesis (FTS) was prepared and evaluated using a silica nanospring (NS) support. FTS offers an approach of producing biofuels from synthesis gas (syngas) produced via biomass gasification. The Fe/NS catalysts were prepared using three different methods: (i) incipient wetness impregnation, (ii) precipitation and (iii) modified sol-gel, in order to obtain different sizes of deposited Fe nanoparticles on the NS support and investigate the influence of particle size on FTS. The Fe decorated catalysts were calcined and then activated with either H 2 , CO or H 2 + CO mixture. The prepared Fe/NS catalysts were characterized before the FT reaction by BET surface area, X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) in order to find correlations between physico-chemical properties of catalysts and catalytic performance. The decoration of Fe nanoparticles of different sizes onto NS using the various methods ranged from 1.7 to 10 nm. The FTS performance was also evaluated in a quartz fixed-bed microreactor (H 2 /CO of 2:1, 270 °C) and the products trapped and analyzed by GC-TCD and GC–MS to determine CO conversion and reaction selectivity. These results show that the highest CO conversion (76.6%) and a wide distribution of light hydrocarbon (C 6 to C 14 ) were obtained for Fe/NS catalyst prepared by impregnation and activated with CO after 12 h of the FT reaction. [ABSTRACT FROM AUTHOR]

This study provides an extensive investigation on the kinetics, combustion characteristics, and thermodynamic parameters of the thermal degradation of guinea grass (Megathyrsus maximus) in N2-pyrolytic and oxidative atmospheres. A model-fitting technique and three different iso-conversional techniques were used to investigate the kinetics of the thermal process, after which an analysis of the combustion characteristics and thermodynamic parameters was undertaken. Prior to this, experiments on the physico-chemical characterization, thermogravimetric, and spectroscopic analyses were carried out to provide insight into the compositional structure of the guinea grass. The volatile matter, fixed carbon, and total lignin contents by mass were 73.0%, 16.1%, and 21.5%, respectively, while the higher heating value was 15.46 MJ/kg. The cellulose crystallinity index, determined by XRD, was 0.43. The conversion of the GG in air proceeded at a relatively much higher rate as the maximum mass-loss rate peak in a 20 K/min read was −23.1 and −12.3%/min for the oxidative and the pyrolytic, respectively. The kinetics investigation revealed three distinctive stages of decomposition with their corresponding values of activation energy. The average values of activation energy (FWO) at the latter stages of decomposition in the pyrolytic processes (165 kJ/mol) were higher than those in the oxidative processes (125 kJ/mol)—an indication of the distinctive phenomenon at this stage of the reaction. The Coats–Redfern kinetic model revealed that chemical reactions and diffusional models played a predominant role in the thermal decomposition process of the GG. This study showed that the thermodynamic parameters varied with the conversion ratio, and the combustion performance increased with the heating rates. The use of GG as an energy feedstock is recommended based on the findings from this work. [ABSTRACT FROM AUTHOR]

The effects of Al2O3 coating on the performance of silica nanospring (NS) supported Co catalysts for Fischer–Tropsch synthesis (FTS) were evaluated in a quartz fixed-bed microreactor. The Co/NS-Al2O3 catalysts were synthesized by coating the Co/NS and NS with Al2O3 by an alkoxide-based sol-gel method (NS-Al-A and NS-Al-B, respectively) and then by decorating them with Co. Co deposition was via an impregnation method. Catalysts were characterized before the FTS reaction by the Brunauer–Emmett–Teller (BET) method, X-ray diffraction, transmission electron microscopy, temperature programmed reduction, X-ray photoelectron spectroscopy, differential thermal analysis and thermogravimetric analysis in order to find correlations between physico-chemical properties of catalysts and catalytic performance. The products of the FTS were trapped and analyzed by GC-TCD and GC-MS to determine the CO conversion and reaction selectivity. The Al2O3 coated NS catalyst had a significant affect in FTS activity and selectivity in both Co/NS-Al2O3 catalysts. A high CO conversion (82.4%) and Σ > C6 (86.3%) yield were obtained on the Co/NS-Al-B catalyst, whereas the CO conversion was 62.8% and Σ > C6 was 58.5% on the Co/NS-Al-A catalyst under the same FTS experimental condition. The Co/NS-Al-A catalyst yielded the aromatic selectivity of 10.2% and oxygenated compounds. [ABSTRACT FROM AUTHOR]

The cell wall compositional (lignin and polysaccharides) variation of two sweet sorghum varieties, Della (D) and its variant REDforGREEN (RG), was evaluated at internodes (IN) and nodes (N) using high-performance liquid chromatography (HPLC), pyrolysis-gas chromatography-mass spectrometry (Py-GCMS), X-ray diffraction (XRD), and two-dimensional (2D) 1 H- 13 C nuclear magnetic resonance (NMR). The stalks were grown in 2018 (D1 and RG1) and 2019 (D2 and RG2) seasons. In RG1, Klason lignin reductions by 16-44 and 2-26% were detected in IN and N, respectively. The analyses also revealed that lignin from the sorghum stalks was enriched in guaiacyl units and the syringyl/guaiacyl ratio was increased in RG1 and RG2, respectively, by 96% and more than 2-fold at IN and 61 and 23% at N. The glucan content was reduced by 23-27% for RG1 and by 17-22% for RG2 at internodes. Structural variations due to changes in both cellulose- and hemicellulose-based sugars were detected. The nonacylated and γ-acylated β-O-4 linkages were the main interunit linkages detected in lignin. These results indicate compositional variation of stalks due to the RG variation, and the growing season could influence their mechanical and lodging behavior.