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Through the reaction of methane reforming with CO2, the influence of calcination temperature on the NiO/MgO catalyst prepared by impregnation was investigated. Results indicated that the NiO/MgO catalyst torrefied at 800°C displayed stronger interactions between metal and support, and also exhibited higher activity. In order to provide further insight into the adsorption and hydrogenated dissociation of CO2, the reaction over both the MgO and NiO/MgO catalysts were separately analyzed by temperature programmed desorption and temperature programmed surface reaction-mass spectrometer. It was demonstrated that the NiO/MgO catalyst calcined at 800°C displayed stronger and more active sites for the adsorption of CO2 and that the presence of surface H would promote the dissociation of CO2 into CO. [ABSTRACT FROM AUTHOR]

HulunBuir lignite pyrolysis at low temperatures with different coal particle sizes, and different heating modes were studied on a fixed-bed reactor in order to investigate the oxygen evolution characteristics. The results show that pyrolysis temperature heavily influences the oxygen evolution. Almost 70.69 wt% of oxygen in lignite transferred into volatile products at 700 °C. With an increase of temperature, the proportion of oxygen transferred into pyrolysis water (water-O) and gas (gas-O), while the proportion of oxygen in tar (tar-O) reached a maximum of 2.26 wt% at 700 °C. The amount of carbonyl groups and ether linkages reached their maxima in char at 600 °C and 650 °C, respectively. After temperature-programmed pyrolysis and isothermal pyrolysis, there was more oxygen in the chars collected from the smaller coal particles, while after solid heat carrier pyrolysis, the coal particle size had little impact on the oxygen amount in chars (Char-O). At the same pyrolysis temperature, heating rate was determined to be one of the main factors that affecting the oxygen evolution. [ABSTRACT FROM AUTHOR]

Three coal macerals with high purities were separated from Pingshuo gas coal. The formation rules of HCN and NH3 during macerals pyrolysis and gasification were investigated. Experiments were carried out in a tubular quartz reactor at atmospheric pressure. The reactor allowed coal particles to be heated up rapidly and held for a prespecified period of time at a peak temperature. The amount of HCN and NH3 were quantified by ion chromatography. The influence of temperature and macerals type on the formation rules of HCN and NH3 was discussed. Results showed that the formation of HCN was mainly due to the thermal cracking of volatile, and NH3 formed both from the thermal cracking of volatile and the cracking of nascent char. The HCN yield increased with an increase in pyrolysis temperature. For three coal macerals (liptinite, vitrinite and inertinite), the yield of HCN depended not only on their volatile contents but also nitrogen-containing functional groups, in which more pyrrole-type nitrogens would form more amount of HCN at lower temperature. The yield of NH3 depended on the ability of forming ‘H’ radical. Under the experiment condition in this study, inertinite could convert more nitrogen into NH3 than vitrinite and liptinite. The yield of HCN during gasification was almost the same as that during pyrolysis, the yield of NH3 during gasification was little higher than that during pyrolysis. [Copyright &y& Elsevier]