Co-combustion is the most attractive option for extending the utilization of Zhundong coals from the newly discovered and the largest intact coalfield in China. However, operational practices have shown that power plants frequently encounter ash deposition problems during co-combustion with Zhundong coals. To address such an issue, in the present work, coal blends of a bituminous coal and a Zhundong sub-bituminous coal, with blending ratios of 90:10, 70:30, 50:50, 30:70, and 10:90 on a weight basis, were burned on a laboratory drop tube furnace at 1350°C. For comparison, combustion experiments of the component coals were also carried out under the same conditions. The resulting ash samples were thoroughly characterized by using a Malvern particle size analyzer and a computer controlled scanning electron microscope. The obtained data were correlated to the ash deposition behavior in co-combustion with Zhundong coals in power plant boilers. The results show that particle mass size distributions of the ash samples from combustion of low-ZD-loaded fuels (with the proportion of the Zhundong coal investigated ≤50 wt %) are similar. The basic and acidic elements are partitioned similarly into ash particles. Ash deposition propensities, evaluated as the ratio of basic to acidic oxides (B/A) of the ash, are all low and show insignificant differences. These are consistent with the similarities in ash deposition behavior during co-combustion with Zhundong coals with low proportions in practical coal-fired boilers. In contrast, the ash properties are apparently different for the fuels with the proportion of the Zhundong coal higher than 50 wt % (denoted as high-ZD-loaded fuels). Small particles of <10 μm are more abundant in the ash samples and are more enriched in basic elements (especially Ca, Fe, and Mg) for the high-ZD-loaded fuels than for the low-ZD-loaded fuels. These data could well explain the more serious ash deposition problems arising during cocombustion with higher proportions of the Zhundong coals in practical boilers. It is also found that, for the ashes from combustion of the high-ZD-loaded fuels, both the amount of the small ash particles and the contents of basic elements in them increase with increasing the proportion of the Zhundong coal in the fuel. These data agree well with field observations of higher ash deposition propensities for coal blends with higher proportions of the Zhundong coals.

No abstract

Experiments were performed to determine the effects of alkali and alkaline earth metallic (AAEM) species on the ignition behavior of char under O2/N2 conditions. The char ignition temperatures of a Loy Yang brown coal were investigated using a wire-mesh reactor, where the secondary reactions of the evolved volatiles were minimized. Water, ammonium acetate, and sulfuric acid sequential extractions were employed to prepare the coal samples of different chemical forms of AAEM compounds from raw coal. In comparison to that of raw coal, the increases in the average char ignition temperature of 33 and 55 °C were observed for ammonium-acetate-extracted coal and sulfuric-acid-extracted coal (H-form coal), respectively, indicating the strong catalytic effects of various chemical forms of AAEM species on the char ignition behavior of brown coal. To find out which chemical form of sodium has a higher catalytic effect on the char ignition behavior, combustion experiments were also carried out for Na-exchanged coals and NaCl-loaded coals, which were prepared from H-form coal. The average char ignition temperature of 0.05 M Na-exchanged coal is 48 °C lower than that of 0.05 M NaCl-loaded coal in air, although those two samples have a close content but different chemical forms of sodium. It was found that sodium in char as carboxylates (−COONa) or NaCl can both improve the ignition characteristics of coal samples but carboxylates (−COONa) show a more significant catalytic effect on the average char ignition temperature in air combustion.

No abstract

In our search for environmentally benign insecticides with high activity, low toxicity and low residue, a novel series of amides containing N-pyridylpyrazole moieties were designed and synthesized. The structures of the title compounds were characterized and confirmed by 1H-NMR and elemental analysis. Furthermore, the structure of compound 7l was determined by single crystal X-ray diffraction. The preliminary bioassay tests showed that some of them exhibited good insecticidal activities against Mythimna separata Walker, Plutella xylostella (Linnaeus, 1758) and Laphygma exigua Hübner.

The effect of the ethylene receptor competitor 1-methylcyclopropene (1-MCP) and the legally approved disinfectant chlorine dioxide (ClO 2 ) on preservation of the green walnut fruit during storage was investigated. Green Chinese walnut fruit cv. Xilin No.2 was harvested on commercial maturity and stored at 0-1°C after the fruit was treated by water (control), 80 mg L −1 ClO 2 (ClO 2 ), 0.5 μLDuring storage, respiration, ethylene production, phenolics content, antioxidative activity, weight changes, decay of the fruit and kernel traits of acid value, peroxide value,free fatty were measured. All treatments decreased postharvest respiration intensity in different degrees and inhibited ethylene production peak. ClO 2 increased the total phenol and flavonoid content of the green fruit compared with other treatments and the control (P < 0.05), but not did the total antioxidant activity for this treatment. After 42-day storage, ClO 2 remained higher fresh weight and lower decay index than control, while 1-MCP increased the fruit decay index.Final acid values of kernel from ClO 2 , control and 0.1 1-MCP+ ClO 2 were not different from their initial values, which from 0.5 1-MCP increased. Final peroxide value for kernel from ClO 2 showed no change during storage but increased at least 1.0-fold for other treatments. ClO 2 preserved 99.9 % of initial free fatty acid, similar to that for the control (99.8 %), whereas 0.5 1-MCP preserved only 95.7 %. ClO 2 is of potential in decay retardation and kernel traits maintenance of green walnut fruit, whereas the 1-MCP has a negative effect for decay control on walnut.

No abstract

In this paper, an economical, green pathway involving the palladium nanoparticles (Pd NPs) catalyzed reductive Ullmann reaction of an aryl chloride to afford a biaryl with high conversion and selectivity in an ionic liquid (IL)/supercritical carbon dioxide (ScCO 2 ) system was developed. The combination of IL and ScCO 2 provides superior advantages in product separation, catalyst recycling and reuse of reaction media over traditional organic solvents. Further investigations showed that the Brønsted-acidic imidazolium IL {e.g., (1-butyl-3-(sulfobutyl)-imidazolium) hydrogen sulfate,