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2-Methyltetrahydrofuran (2-MTHF) is a promising fuel additive and renewable solvent. Herein, we report a selective hydrodeoxygenation of cellulose-derived γ-valerolactone (GVL) to 2-MTHF under mild conditions over silica-supported RhRe and RhMo bimetallic catalysts. RhMo/SiO2showed the best performance for the target 2-MTHF with a high selectivity of 86% in heptane at 120 °C. The high catalytic performance of Rh-based catalyst was attributed to an acidity induced by the presence of additional metals such as Mo or Re. However, the acidity in aqueous phase was weaker than that in heptane, requiring additional acid sites. ZSM-5 performed best in combination with the bimetallic catalysts, resulting in the selectivity of 76% to 2-MTHF even in water at 120 °C. Moreover, a high reaction temperature (160 °C) caused hydrodeoxygenation of 2-MTHF and enabled perfectly selective production of alkanes with butane and pentane as predominant products.

Chars from 20 lignite samples were prepared from two types of original lignites by multistage removal of inherent metallic species and subsequent pyrolysis and then were gasified with CO2. A kinetic model, which assumed the progress of noncatalytic and catalytic gasification in parallel, quantitatively described the time-dependent changes in char conversion up to 0.999 for all the chars by employing multicatalytic species having different initial activities and deactivation kinetics. A single piecewise linear function, which followed a nucleation–growth mechanism of the catalysts, showed the relationship between the total concentration of Na, K, Ca, and Fe and the initial total catalytic activity (ICA-2) for the chars. The overall rate of catalyst deactivation (ICD-2) was given by a single linear function of ICA-2 and a factor for the composition of metallic species. This function was also applicable to previously reported ICA-2/ICD-2 relationships for chars from lignite and biomass, showing fast deactivation of Fe catalyst and an important role of Mg in the promotion of catalyst deactivation.

A total of 18 chars from the pyrolysis of six trios of sugar cane bagasses (SCBs; original, water-washed, and acid-washed) were gasified with CO2at 900 °C, aiming at a quantitative description of the rate of gasification catalyzed by inherent metallic species and a correlation of the catalytic activity and its change during the gasification with the metallic species composition. The measured kinetics was described quantitatively over a range of char conversion, 0–0.999, by a model that assumed progress in parallel of the catalytic gasification and non-catalytic gasification, together with the presence of a catalytic precursor and three to four types of catalysts having different activities and deactivation characteristics. A series of regression analyses was scrutinized and reached expression of initial catalytic activity as a linear function of Na, K, Ca, Fe, and Si concentrations in the char with a correlation factor (r2) of >0.98. The catalyst precursor contributed fully by water-soluble Na, K, and Ca. Si was responsible for the catalyst deactivation during the pyrolysis but not during the gasification. The chars produced from original SCBs followed a linear relationship between the initial catalytic deactivation rate and initial activity (r2> 0.99), while such a linear relationship was not valid for those formed from the water-washed SCBs. This was explained mainly by more rapid deactivation of the Fe catalyst in the chars from water-washed SCBs than that in the chars formed from the original SCBs. Na and K in char from the original SCBs, originating from the water-soluble SCBs, chemically interacted with the Fe catalyst, slowing its deactivation.

In continuation of our previous study on production of high-strength metallurgical coke from torrefied softwood (cedar), we studied coke production from a mixture of torrefied cedar (TC) and noncaking coal by pulverization to sizes <100 μm, mixing, binderless hot briquetting, and carbonization. These sequential processes produced coke with a tensile strength of 5–17 MPa, which was equivalent to or greater than that of conventional coke (5–6 MPa), from TC-coal mixtures over the entire ranges of TC mass fraction in briquette of 0–100%, torrefaction temperature of 250–300 °C, and choice of coal (sub-bituminous or medium-volatile bituminous coal). The mixing of TC and coal hindered densification of coke due to hindrance of shrinkage of more-shrinkable TC-derived particles during the carbonization under many of the conditions. Nevertheless, positive synergy occurred in the coke strength at TC mass fractions of over 50%, where coal-derived particles were dispersed in the matrix of TC-derived particles, bonded to them during the carbonization, and behaved as a reinforcement of the matrix. The bonding between TC-derived and coal-derived primary particles was revealed by scanning electron microscopy. Copulverization of mixed TC and coal to sizes <40 μm before the briquetting gave cokes having strengths as high as 23–28 MPa. The fine pulverization increased the frequencies of mutual bonding of TC-derived particles and coal-derived particles and bonding between TC-derived and coal-derived particles per coke volume. The strength of coke from the TC-coal mixture generally followed volume-based additivity of strengths of cokes from TC and coal. This was realized by mixing primary particles of TC and coal within ≈10 μm scale or even smaller.