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Four pairs of raw and acid-washed brown coals were subjected to pyrolysis and in-situ steam gasification at 900 °C in fixed-bed reactors with or without forced gas flow through the bed of char particles. The chars from the acid-washed coals were gasified obeying a first-order kinetics with respect to the fraction of unconverted char regardless of the presence/absence of forced gas flow. Its presence/absence considerably influenced the gasification kinetics of the chars from the raw coals, even altering the manner of change in the rate of gasification with time and the char conversion, such as the apparent order of reaction. It was found that alkali and alkaline earth metallic (AAEM) species were allowed to stay in/on the char in the absence of the forced gas flow but volatilized extensively in its presence. Thus, the catalysis of AAEM species diminished in the presence of forced gas flow much quicker than in its absence, in which the catalysis was lost exclusively by intraparticle deactivation of AAEM species. The char conversion was quantitatively described as a function of time by a kinetic model that considered the progress of catalytic and noncatalytic gasification in parallel and also the loss of catalysis along with the progress of gasification.

Nascent volatiles from the pyrolysis of a type of woody biomass were reformed in a bed of charcoal at 750À850 °C. While the volatiles passed through the bed together with air at an air ratio of 0.115, the concentration of heavy tar (bp > 336 °C) decreased from 910 000 to 6À1020 mg/Nm 3 dry . This rapid and almost total decomposition of the tar can be ascribed to its deposition onto the charcoal surface, forming coke. The coke formation leads to the loss of the charcoal micropores that provide active sites. Therefore, simultaneous creation of micropores by gasification is necessary to maintain the charcoal activity. Steam played the role of gasifying agent, while O 2 was consumed mainly by gas-phase oxidation that supplied the heat for the reaction.

Pyrolysis bio-oil is a promising source of liquid fuels, but requires upgrading to remove excess oxygen and produce a satisfactory fuel oil. Nickel phosphide has been shown to be an active composition for hydrodeoxygenation (HDO) of bio-oil model compounds. In this study, nickel phosphide catalysts were used for direct upgrading of an actual pyrolysis bio-oil derived from cedar chips. The activity of Ni 2 P deposited on an amorphous SiO 2 support for HDO was first verified using the model compound, 2-methyltetrahydrofuran (2-MTHF), at the temperature of the pyrolysis oil treatment of 350 o C. The Ni 2 P/SiO 2 catalyst showed high activity for 2-MTHF hydrodeoxygenation under atmospheric pressure hydrogen with low cracking activity. Fast pyrolysis and catalytic upgrading were conducted sequentially using a laboratory-scale, two-stage system consisting of a fluidized bed pyrolyzer and a fluidized bed catalytic reactor both operating at 0.1 MPa, with a hydrogen partial pressure of 0.06 MPa. It was found that the Ni 2 P/SiO 2 catalyst was moderately effective in upgrading the biomass pyrolysis vapors and producing a refined bio-oil with decreased oxygen content. The deoxygenation of the bio-oil was confirmed by elemental analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis. Gas chromatography-mass spectrometry (GC-MS) analysis showed that the treated bio-oil mainly consisted of phenolic compounds, and the MS spectra before and after upgrading suggested that reactions including hydrodeoxygenation, hydrogenation, decarbonylation, and hydrolysis occurred during the upgrading. Furthermore, Ni 2 P supported on ZSM-5 zeolite eliminated oxygen in the bio-oil with smaller reduction in the oil yield than Ni 2 P supported on SiO 2. The deoxygenation of the nickel phosphide catalysts was higher than that of conventional catalysts such as Pd/C and an FCC-catalyst.

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This paper discusses gasification of solid fuels, such as biomass and lignite, at temperatures well below 1000 °C, which potentially realizes a loss of chemical energy (LCE) smaller than 10% but encounters difficulty in fast and/or complete solid-to-gas conversion in conventional reactor systems. First, key thermochemical and catalytic phenomena are extracted from complex reactions involved in the gasification. These are interactions between intermediates (i.e., volatiles and char), catalysis of inherent and extraneous metallic species, and very fast steam gasification of nascent char. Second, some ways to control the key phenomena are proposed conceptually together with those to rearrange homogeneous/heterogeneous reactions in series/ parallel. Third, implementation of the proposed concepts is discussed assuming different types of gasifiers consisting of a singlefluidized bed, dual-fluidized bed, triple-bed circulating fluidized bed, and/or fixed (moving) bed. The triple-fluidized bed can attain gasification with a LCE as small as 10% by introducing enhancement and/or elimination of the key phenomena and another way to recuperate heat from gas turbine and/or fuel cells (i.e., power generators in gasification combined cycles) into chemical energy of fuel gas. A particular type of fixed-bed gasifier is proposed, which is separated from a pyrolyzer to realize not only control of the key phenomena but also temporal/spatial rearrangement of exothermic and endothermic reactions. This type of gasifier can make a LCE smaller than 4%. Even a conventional single-fluidized bed provides simple and effective gasification, when tar-free/reactive char is used as the fuel instead of parent the one and contributes to a novel integrated gasification fuel cell combined cycles with a theoretical electrical efficiency over 80%.

This paper describes fundamental experiments of a new biomass ironmaking that employs low-grade iron ore and woody biomass for promoting the direct reduction, FeO + C ) Fe + CO, in which dehydrated, porous limonite iron ore was filled with carbon deposited from the biomass tar, biotar. In our experiments, three types of iron ores containing different amounts of combined water (CW; 1.6, 3.8, and 9.0 mass %) were first dehydrated at 450°C to make them porous and then heated with pine tree biomass at 500-600°C for the gasification and the tar vapor generated was decomposed to deposit carbon within/on the porous ores. The dehydration treatment made the iron ores porous by removing CW and significantly increased their Brunauer-Emmett-Teller (BET) specific surface areas and porosities. In the second treatment of biomass gasification and decomposition of tar vapor, the biomass was changed into char, tar vapor, and reducing gas; the biotar was decomposed and carbonized within the porous ores. Interestingly, the ores caught biotar effectively, not only on the surface but also inside their pores. Here, the ores with the nanosized pores served as catalysts for tar carbonization with gas generation. Simultaneously, the ores were partially reduced to magnetite by the reducing gas. The ores containing carbonized material were easily reduced to iron by only heating until 900°C in a nitrogen atmosphere; this was due to the direct contact of carbon and iron oxide within the ores, so-called direct reduction. In conclusion, the dehydrated limonite iron ore was most effective for avoiding the generation of sticky tar in the biomass gasification and for filling the porous ore with carbon from tar. The product is a promising raw material for biomass ironmaking. The results appealed an innovative ironmaking method with a large reduction of carbon dioxide emission using low-grade iron ore and woody biomass.

This paper describes the synthesis of copper/copper oxide nanoparticles via a solution plasma, in which the effect of the electrolyte and electrolysis time on the morphology of the products was mainly examined. In the experiments, a copper wire as a cathode was immersed in an electrolysis solution of a K 2 CO 3 with the concentration from 0.001 to 0.50 M or a citrate buffer (pH ¼ 4.8), and was melted by the local-concentration of current. The results demonstrated that by using the K 2 CO 3 solution, we obtained CuO nanoflowers with many sharp nanorods, the size of which decreased with decreasing the concentration of the solution. Spherical particles of copper with/ without pores formed when the citrate buffer was used. The pores in the copper nanoparticles appeared when the applied voltage changed from 105 V to 130 V, due to the dissolution of Cu 2 O.