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The cell wall compositional (lignin and polysaccharides) variation of two sweet sorghum varieties, Della (D) and its variant

Chlorella vulgaris algae is comprised of a complex mixture of compounds such as carbohydrates, lipids, and proteins and is a suitable feedstock for biofuels. The aim of this study was to convert commercial and a low cost field cultivated algae, via pyrolysis, to produce bio-oil, synthesis gas, and biochar products. The thermal degradation behaviour of algae was investigated by thermogravimetric analysis. Proximate, ultimate, fatty acid methyl ester and carbohydrates analyses, and pyrolysis–GCMS were further employed to characterize the chemical components of algae. Commercial and field cultured C. vulgaris algae was pyrolyzed (450, 500, and 550 °C) and their pyrolysis products were collected and characterized. The highest biochar yield was 42% at 450 °C and the highest bio-oil yield was 47.7% at 550 °C. The biochar physical and chemical properties were assessed using proximate and ultimate analysis, calorific value, specific surface area, butane absorption activity, Raman spectroscopy, and electron microscopy. Algae biochar was found to be mostly composed of condensed phenolic compounds and majorly disordered amorphous carbon. The bio-oils were characterized by the combination of GC–MS, high-pressure liquid chromatography, and electrospray ionization mass spectrometry. Fatty acids, carbohydrates, nitrogen-containing compounds, and aromatic hydrocarbons were abundantly found in the algae bio-oil.

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 (H2-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 (H2/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 C6-C16 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.

The reduction of cobalt (Co) catalyst supported on silica nanosprings for Fischer-Tropsch synthesis (FTS) has been monitored by X-ray photoelectron spectroscopy (XPS) and compared to FT catalytic activity. The cobalt is present in the starting catalyst as a Co3O4 spinel phase. A two-step reduction of Co3O4 to CoO and then to Co0 is observed, which is consistent with the results of H2-temperature programmed reduction. During the reduction the two steps occur concurrently. The deconvolution of the Co 2p core level state for the catalyst reduced at 385 °C and 1.0 × 10−6 Torr of H2 revealed signatures of Co0, CoO, and Co3O4. The reduction saturates at a Coo concentration of approximately 41% after 20 h, which correlates with the activity and lifetime of the catalyst during FTS testing. Conversely, at 680 °C and 10 Torr of H2, the catalyst is completely reduced after 10 h. The evolution of the Co d-band at the Fermi level in the valence band XPS spectrum definitively verifies the metallic phase of Co. FTS evaluation of the Co/NS catalyst reduced at 609 °C showed higher production rate (3-fold) of C6-C17 hydrocarbons than the catalyst reduced at 409 °C and is consistent with the XPS analysis.

The effect of ethylene diamine tetraacetic acid (EDTA) modification on the physico-chemical properties and catalytic performance of silica nanosprings (NS) supported cobalt (Co) catalyst was investigated in the conversion of syngas (H2 + CO) to hydrocarbons by Fischer-Tropsch synthesis (FTS). The unmodified Co/NS and modified Co/NS-EDTA catalysts were synthesized via an impregnation method. The prepared Co/NS and Co/NS-EDTA catalysts were characterized before the FTS reaction by BET surface area, X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), differential thermal analysis (DTA) and thermogravimetric analysis (TGA) in order to find correlations between physico-chemical properties of catalysts and catalytic performance. FTS was carried out in a quartz fixed-bed microreactor (H2/CO of 2:1, 230°C and atmospheric pressure) and the products trapped and analyzed by GC-TCD and GC-MS to determine CO conversion and reaction selectivity. The experimental results indicated that the modified Co/NS-EDTA catalyst displayed a more-dispersed phase of Co3O4 nanoparticles (10.9%) and the Co3O4 average crystallite size was about 12.4 nm. The EDTA modified catalyst showed relatively higher CO conversion (70.3%) and selectivity toward C6–18 (JP-8, Jet A and diesel) than the Co/NS catalyst (C6–14) (JP-4).

As the most abundant municipal solid waste, corrugated cardboard (CCB) is a suitable resource for thermochemical conversion into various solid and liquid products. CCB samples were pyrolyzed at three temperatures (350, 400, and 450 °C) and their pyrolysis products (bio-oil and biochar) were characterized and analyzed. Thermogravimetric analysis (TGA) was utilized to study the thermal degradation behavior of CCB. CCB and biochar samples were subjected to proximate, ultimate, lipid and carbohydrates analyses, and Py–GCMS to characterize their chemical components. The highest biochar yield was 75% at 350 °C, and the highest bio-oil yield was 47% at 450 °C. The biochar physical and chemical properties were also assessed using calorific values, specific surface area, Fourier-transform infrared (FTIR) and Raman spectroscopies, and x-ray diffraction (XRD). Biochar was found to have low ash and nitrogen contents. The bio-oil was characterized by the combination of GCMS, high-performance liquid chromatography (HPLC), and electrospray ionization mass spectrometry (ESI–MS). The molar mass distribution and an estimate of monomer/oligomer ratio were determined from ESI-MS data. The bio-oil contained a complex mixture of pyrans, furans, phenols, and cyclopentenes. Levoglucoson was abundantly found in the bio-oil, suggesting the suitability of cardboard pyrolysis products for further processing into fuels.