In fast catalytic pyrolysis of eucalyptus as woody biomass, zeolites enhanced the formation of aromatic hydrocarbons with and without O-atoms, mainly. H-ZSM-5 and H-Beta zeolites were efficient for the formation of non-oxygenated aromatic compounds. High Si/Al2 ratio in H-ZSM-5 depressed the formation of non-oxygenated aromatics, while high Si/Al2 ratio in H-Beta kept high yield of non-oxygenated aromatics. H-mordenite and USY showed a moderate catalytic activity for the formation of phenolic compounds as well as non-oxygenated aromatics, due to moderate catalytic properties. Aromatic compounds may be derived from cellulose, hemicellulose and lignin. In the case of cellulose or hemicellulose as source of aromatics, oxygenated intermediates were formed by thermal decomposition of cellulose or hemicellulose, followed by reaction to form aromatic compounds. In the case of lignin source, oxygenated aromatics were formed by thermal decomposition of lignin, followed by deoxygenation to form non-oxygenated aromatics. Strong solid acidity favors deoxygenation reaction. Moderate solid acidity leads to the formation of phenolic compounds. Large micropore diameter and 3-dimensional microstructure have advantage, since intermediates can contact active sites inside the micropore. Except for SAPO-34, 4A, 13X and Ti-silicate, exhibiting significantly low yield of both of non-oxygenated aromatics and phenols, there seems to be an inversed correlation between yield of non-oxygenated aromatic compounds and that of phenolic compounds.
Along with Japanese cedar bark, fir bark and Japanese larch bark were pyrolyzed to estimate the possibility of utilizing these softwood barks as resources for fine chemicals by comparing the pyrolysis product compositions. The three softwood barks contained higher ash content and yielded lower amount of volatiles when compared with cedar heartwood. The major pyrolysis products from their barks were similar to those previously reported from softwood trunks. Levoglucosan was a major pyrolysis product formed from the three softwood barks, despite being a minor product from wood trunk pyrolysis. Therefore, softwood barks can be expected as a feedstock for production of levoglucosan. An increase in the moisture content in the cedar bark generated more pyrolysis products. This result indicates that softwood barks do not require drying prior to pyrolysis, which simplifies the pyrolysis system.
Empty fruit bunches (EFB) of oil palm are the lignocellulosic waste from crude palm oil production. The current practice to deal with the waste is either to burn EFB for energy production or to spread them back on the field as a fertilizer. Both options offer a limited additional value to the industry compared to the use of EFB as a renewable resource for chemicals production. To be used as the raw materials for chemicals production, EFB needs to be hydrolysed first to its sugar-monomer content. This manuscript presents the study of enzymatic hydrolysis of EFB by xylanolytic enzyme. The study covers the evaluation of commercial xylanolytic enzyme in hydrolysing EFB, the effect of temperature, pH, substrate concentration and potential inhibitors in the EFB hydrolysis process, and the influences of thermal pretreatment for enhancing the yield of hydrolysis. The results of this study lead to an increase in the enzymatic hydrolysis process of EFB. The maximum hydrolysis yield was obtained at temperature of 60 ℃ and pH of 5. Both inhibitors, xylose and glucose, affected the hydrolysis process. The results showed that the thermal pretreatment of EFB enhanced the enzymatic hydrolysis yield. Enzymatic hydrolysis was shown to follow Michaelis Menten kinetic model, and the kinetic parameters were obtained to be Km = 22.16 g/L and Vm = 0.17 g/L/min.
This work aims at investigating correlations between primary pyrolysis characteristics of lignin and chemical structure of lignin feedstock. Three different types of lignin samples were prepared through enzymatic hydrolysis, organosolv extraction, and Klason procedure. Analysis by FT-IR and solid state 13C-NMR revealed that the lignin samples exhibited different contents of aromatic carbons, connection carbons, methoxyl carbons, and aliphatic side chains. The three lignin samples were pyrolyzed in a two-stage-tubular reactor at 650 ℃, and pyrolysis products were analyzed with gas chromatographs on-line. More than fifty compounds including inorganic gases, light hydrocarbons (LHs), aromatic hydrocarbons (AHs), phenol derivatives and light non-phenolic oxy-compounds (NPOCs) were gaschromatographically separable and quantified. The influence of the lignin structures on the pyrolysis characteristics was studied, and the correlation of product distribution and lignin chemical structures was examined. The total carbon selectivity into char and tar was increased with increasing lignin aromaticity. Methoxyl group and aliphatic substituents likely contributed for enhancing char formation, while hydrogen in lignin enhanced tar formation. Yields of LHs and NPOCs were increased with increasing aliphatic carbons of the lignin samples. AHs were formed from gas-phase recombination of LHs such as olefins, diolefines and alkynes, rather than directly from aromatic structures in the original lignin likely because of high energy required to cleavage carbon-oxygen bond existed in major structural units such as syringols or guaiacols.
The main challenges facing the commercialization of biodiesel are: profitability, feedstock availability and low cost efficient production process. Although worldwide production of vegetable oil feedstocks is sufficient enough, big area of land needed for cultivating such feedstocks is the major drawback. Algae-biomass (including macro- and microalgae) is gaining interest from many current researchers as they have potential to provide sufficient fuel for global consumption. Algae can be produced fast with high lipid content. Moreover, it can provide food avoiding future starving and allow replacing fossil fuels through carbon-neutral biofuels for combustion machines in the transport, industrial and agricultural sectors. In this study, high grade biodiesel was produced from microalgae derived lipids (Nannochloropsis oculata) via transesterification reaction with methanol using calcium methoxide catalyst. The results showed excellent performances with high yield (92 %) of biodiesel at 60 ℃ compared to the highest yield reported at 22 % with using MgZr catalyst. Interestingly, calcium methoxide catalyst could be also successively reused for five times with the maintained biodiesel yield. Biodiesel produced from microalgae oil had high content of polyunsaturated fatty acids, which made it highly suitable as winter grade biodiesel.
AC impedance spectroscopic approach is applied into room temperature ionic liquid (RTIL) based mixtures. The RTIL is hydrophobic 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C2mim][TFSI]. For higher efficient electric double layer capacitor (EDLC) as an energy storage device, Cu3Au nanoporous electrode is assembled in the [C2mim][TFSI]-propanol mixtures. Due to high cost and high viscosity of the pure [C2mim][TFSI], an additive is required in order to achieve the low cost and quick electrochemical response for rapid charge/discharge. Propanol having relative low vapor pressure among alcohols is adequate to reduce viscosity of the hydrophobic RTILs. With nanoporous metallic electrode, the EDL capacitance in the mixtures exceed that in the pure [C2mim][TFSI]. Also, the capacitance in the mixtures was large enough up to 80 mol% propanol. In addition, isomer effect of propanol was seen in the AC impedance spectra.