There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

https://www.massey.ac.nz/~ychisti/Biodiesel.pdf

Biodiesel from microalgae.

Fast pyrolysis utilizes biomass to produce a product that is used both as an energy source and a feedstock for chemical production. Considerable efforts have been made to convert wood biomass to liquid fuels and chemicals since the oil crisis in mid-1970s. This review focuses on the recent developments in the wood pyrolysis and reports the characteristics of the resulting bio-oils, which are the main products of fast wood pyrolysis. Virtually any form of biomass can be considered for fast pyrolysis. Most work has been performed on wood, because of its consistency and comparability between tests. However, nearly 100 types of biomass have been tested, ranging from agricultural wastes such as straw, olive pits, and nut shells to energy crops such as miscanthus and sorghum. Forestry wastes such as bark and thinnings and other solid wastes, including sewage sludge and leather wastes, have also been studied. In this review, the main (although not exclusive) emphasis has been given to wood. The literature on woo...

Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review

Sustainable economic and industrial growth requires safe, sustainable resources of energy. For the future re-arrangement of a sustainable economy to biological raw materials, completely new approaches in research and development, production, and economy are necessary. The ‘first-generation’ biofuels appear unsustainable because of the potential stress that their production places on food commodities. For organic chemicals and materials these needs to follow a biorefinery model under environmentally sustainable conditions. Where these operate at present, their product range is largely limited to simple materials (i.e. cellulose, ethanol, and biofuels). Second generation biorefineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing including pyrolysis, Fisher Tropsch, and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This review focus on cost effective technologies and the processes to convert biomass into useful liquid biofuels and bioproducts, with particular focus on some biorefinery concepts based on different feedstocks aiming at the integral utilization of these feedstocks for the production of value added chemicals.

http://staff.cimap.res.in/PublicationFiles/Renew_Sustain_Energ_Rev_14_578.pdf

Production of first and second generation biofuels: A comprehensive review

Isolation of cellulose fibers from wetland reed grass through an integrated subcritical water hydrolysis-pulping-bleaching process

In this work, hydrogenation of aromatic compounds in light gas oil derived from Athabasca bitumen was carried out using a single- and two-stage hydrotreating processes. Experiments were performed in a trickle-bed reactor using two catalysts namely NiMo/Al2O3 and NiW/Al2O3. NiMo/Al2O3 was used in the first stage for nitrogen and sulphur containing heteroatoms removal whereas NiW/Al2O3 was used in the second stage for saturation of the aromatic rings in the hydrocarbon species. Temperature and liquid hourly space velocity (LHSV) were varied from 350-390°C and 1.0-1.5 h−1, respectively, while pressure was maintained constant at 11.0 MPa for all experiments. Results from single-stage were compared with those from two-stage process on the basis of reaction time. Kinetic analysis of the single-stage hydrotreating process showed that HDA and HDS activities were retarded by the presence of hydrogen sulphide that is produced as a by-product of the HDS process. However, with inter-stage removal of hydrogen sulphide in the two-stage process, significant improvement of the HDA and HDS activities were observed.

Experimental and Kinetics Studies of Aromatic Hydrogenation in a Two-Stage Hydrotreating Process using NiMo/Al2O3 and NiW/Al2O3 Catalysts

Cu-ZnO-based catalysts are of importance for CO2 utilization to synthesize methanol. However, the mechanisms of CO2 activation, the split of the C=O double bond, and the formation of C-H and O-H bonds are still debatable. To understand this mechanism and to improve the selectivity of methanol formation, the combination of strong electronic adsorption (SEA) and atomic layer deposition (ALD) was used to form catalysts with Cu nanoparticles surrounded by a non-uniform ZnO layer, uniform atomic layer of ZnO, or multiple layers of ZnO on porous SiO2. N2 adsorption, H2 temperature-programmed reduction (H2-TPR) X-ray diffraction (XRD), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX), CO-chemisorption, CO2 temperature-programmed desorption (CO2-TPD), X-ray adsorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) were used to characterize the catalysts. The catalyst activity was correlated to the number of metallic sites. The catalyst of 5 wt% Cu over-coated with a single atomic layer of ZnO exhibited higher methanol selectivity. This catalyst has comparatively more metallic sites (smaller Cu particles with good distribution) and basic site (uniform ZnO layer) formation, and a stronger interaction between them, which provided necessary synergy for the CO2 activation and hydrogenation to form methanol.

Atomic Layer Deposition ZnO Over-Coated Cu/SiO2 Catalysts for Methanol Synthesis from CO2 Hydrogenation

Fischer–Tropsch synthesis (FTS) is one of the promising technologies to produce liquid fuels and fine chemicals from coal, natural gas and biomass. Significant improvements in reactor technology and catalyst development are the focus of research in this area. In this work, the effects of 1.0 wt% promotor such as Mn, Mg, Co and Ni on the FTS activity and selectivity of mesoporous alumina supported KCuFe catalyst were studied. All synthesized promoted catalysts were characterized using BET, XRD, H2-TPR, XPS, TEM and XANES. The FTS reaction was carried out in a fixed bed reactor at 270 °C, 300 psi, 2000 h−1 and H2/CO = 1.25. In this work, the Ni-promoted catalyst showed the highest methane selectivity (∼29 %). The Co-promoted catalyst showed the least Olefins/Paraffins (O/P) ratio and a ∼5% increase in methane selectivity. Mg-promoted catalyst performed average but better than Ni and Co-promoted catalysts. However, Mn-supported catalyst outperformed Mg, Ni and Co-promoted catalysts and resulted in higher C5+ selectivity along with a marginal increase in CO conversion. The ∼5%, 2%, and 2% decline in CO2, CH4 and C2-C4 selectivities were also registered upon the addition of Mn promotor. The improvement in FTS activity and selectivity of Mn-promoted catalyst is related to the increase in iron dispersion and reducibility, as seen during H2-TPR, XPS and XANES analyses. The presence of Mn+3 and Mn+4, as confirmed by Mn 2p XPS and Mn K-edge XANES, indicates that the interaction at the electronic level between manganese and iron has contributed to improved performance. This study concludes that Mn is the most effective promotor for the synthesized mesoporous alumina supported KCuFe catalyst for the FT synthesis process.

Ajay K. Dalai

Papers

Isolation of cellulose fibers from wetland reed grass through an integrated subcritical water hydrolysis-pulping-bleaching process

Experimental and Kinetics Studies of Aromatic Hydrogenation in a Two-Stage Hydrotreating Process using NiMo/Al2O3 and NiW/Al2O3 Catalysts

Atomic Layer Deposition ZnO Over-Coated Cu/SiO2 Catalysts for Methanol Synthesis from CO2 Hydrogenation

Effects of promoters (Mn, Mg, Co and Ni) on the Fischer-Tropsch activity and selectivity of KCuFe/mesoporous-alumina catalyst

Catalytic hydrothermal co-gasification of canola meal and low-density polyethylene using mixed metal oxides for hydrogen production