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Coal loaded with inherently-water-soluble sodium was prepared with dicyclohexyl-18-crown-6 to investigate the effects of inherently-water-soluble sodium on temperature-programmed isothermal gasification. The results were compared with Na2CO3-loaded coal using thermo-gravimetric analysis (TGA), and the results showed that sodium had a catalytic effect on gasification, and water-soluble sodium had a stronger catalytic ability than Na2CO3. The isothermal gasification reaction of inherently-water-soluble-sodium-loaded coal was complete in 4.68 min, whereas that of Na2CO3-loaded coal was complete in 5.39 min. Chemisorption of CO2 to chars was investigated by TGA at 300 C, which showed that the order of CO2 chemisorption capacity was similar to that of the catalytic abilities during gasification. Therefore, the CO2 chemisorption capacity accurately reflects differences in the gasification reactivity. Moreover, the distribution of sodium in coal and char structures were investigated by multiple techniques, including scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). EDS-mapping images of Na-loaded coal indicated that inherently-water-soluble sodium mainly adhered to coal particles. This finding shows that coal graphitization was strongly inhibited by inherently-water-soluble sodium, which further strengthened the chemisorption of CO2 to char and the reactivity of char during gasification.

An inherent water-soluble sodium-loaded coal sample was prepared using crown ether for this study. The pyrolysis process of an inherent water-soluble sodium-loaded coal sample and a water-soluble sodium compound-loaded coal sample was researched by thermogravimetric analysis (TGA). Also, the pyrolysis kinetics of the coal samples were analyzed and researched by the distributed activation energy model (DAEM). The results show that the inherent water-soluble sodium is mainly concentrated on coal particles, which further aggravates the degree of the pyrolysis reaction. The presence of sodium can promote the weight loss of coal samples in the preliminary stage of pyrolysis and the thermal condensation stage, block the escape of volatile matter during the main pyrolysis period, and inhibit the process of graphitization of char. The activation energy of pyrolysis increases with the carbon conversion rate, and the presence of sodium can reduce the activation energy under the same carbon conversion rate.

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A comprehensive study was conducted to assess the co-gasification characteristics of sewage sludge and high-sodium coal. As the gasification temperature increased, the CO2 concentration was decreased, and the concentrations of CO and H2 were increased, while the change of CH4 concentration was not obvious. As the coal blending ratio increased, the H2 and CO concentrations initially increased and then decreased, while the CO2 concentration initially decreased and then increased. The mixture of sewage sludge and high-sodium coal shows the synergistic effect of co-gasification, and the synergistic effect was to promote the gasification reaction positively. The average activation energies of co-gasification reactions were calculated by the OFW method, and the average activation energy initially decreases and then increases as the coal blending ratio increases. Both fluidized-bed gasification and thermogravimetric analyzer gasification show that the optimum coal blending ratio is 0.6. Overall, these results provide a theoretical basis for the industrial application of sewage sludge and high-sodium coal co-gasification.

With a thermo gravimetric analysis apparatus combustion characteristics experiments of sawdust, corn straw and mixtures of them were done at 10,20,40℃/min heating rate. The combustion activation energy was acquired by kinetics analysis. The experiment results show that the ignition characteristic and synthesis combustion of corn straw are better than sawdust. The mixture of corn straw and sawdust was easier than each one of them by compression molding.

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A dual-band high-precision lightning imaging spectrometer (DHLIS) is designed to capture the fine spectrum of transient lightning. DHLIS improves the theoretical spectral resolution limit to 1 0 − 3 n m and broadens the spectral range to 30–40 nm by employing double echelle gratings in the arms of a spatial heterodyne spectrometer. Four strong and three fine spectral lines are selected to retrieve the temperature of the lightning channel using the Boltzmann plot method. The experimental results indicate that the inversion accuracy of the temperature obtained by inserting fine spectral lines is higher than that by implementation of four strong spectral lines.