Four different mixed fuels consisted of leather waste, coal, and sewage sludge were combusted in a lab-scale entrained flow fluidized bed furnace. The influence of blending ratio on emission characteristics of SO2, NOx, HCl, particulate matter (PM), heavy metals, and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) was studied. Results showed that the mixing of coal with sewage sludge had a complex effect on the emission characteristics. On the one hand, with more sewage sludge blending in the mixed fuel, the acid gas pollutant (SO2, NOx) decreased a lot, and the recovery of volatile heavy metals (Cd, Pb) increased at the same time. Furthermore, the leaching toxicity of Cr in the fly ash and bottom ash went down below the national standard with the adding of sewage sludge. On the other hand, the mixing of sewage sludge which consisted of more ash content resulted in the increase of the PM emission. Moreover, the high content of Cu and chlorine in the sewage sludge can promote the formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) when the fuel 3 and 4 were combusted. Most importantly, the concentration of toxic PCDD/Fs in the flue gas produced from fuel 3 and fuel 4 was successfully controlled down below 0.20 ng I-TEQ/Nm3 by the active carbon.
ABSTRACT To explore environmentally benign solvents for the absorption of NO and NO2, a series of caprolactam tetrabutyl ammonium halide ionic liquids were synthesized. The solubility of NO and NO2 was measured at temperatures ranging from 298.2 to 363.2 K and atmospheric pressure, and the following trend in the solubility of NO and NO2 in ionic liquids with various halide anions was observed, respectively: F > Br > Cl and Br > Cl > F. Moreover, as the temperature increased from 308.15 to 363.15 K and the mole ratio of caprolactam increased from 2:1 to 6:1, the solubility of NO increased. Alternatively, the solubility of NO2 decreased as the temperature increased from 298.15 to 363.15 K, and the mole ratio of caprolactam increased from 2:1 to 6:1. The absorption and desorption of NO and NO2 was practically reversible in the ionic liquids, which was characterized by nuclear magnetic resonance. The method, which is at least partially reversible, offers interesting possibilities for the removal of NO and NO2.
IMPLICATIONS Basic ionic liquids with amino groups were synthesized and used to capture CO2, SO2, and H2S, and to promote hydrogenation of CO2. In this paper, the authors used caprolactam tetrabutyl ammonium halide ionic liquid (IL) as absorbing medium in which NOx could be absorbed. NOx desorbed from the absorbent could be efficiently reduced by right catalysts at high temperature. The absorbed NO and NO2 gas could be desorbed at higher temperature, allowing the ionic liquids to be reused several times without loss of capability. It was believed that caprolactam tetrabutyl ammonium bromide (CPL-TBAB) ILs may be useful for NOx removal reagent for pollution control. 相似文献
Though polychlorinated biphenyls (PCBs) have distributed as threats in the environment to human beings for several decades, monitoring of trace level PCBs in-field is still a challenge. As a potential method for monitoring PCBs at trace levels, Raman spectroscopy has been used to detect several PCBs in the laboratory. To facilitate the development of rapid detection of PCBs by Raman spectroscopy, it is essential to investigate the Raman spectra of all PCB congeners. Herein, the stable configurations and vibrational spectra of all the PCB congeners were calculated by Gaussian 03 program package. Based on molecular symmetry, PCBs are classified into seven groups. The structural features and the normal vibration modes for each group are discussed. Taking the C(2)-2 group as an example, the wavenumber ranges of the various normal vibration modes in the Raman spectra of PCBs were analyzed. The accuracy of calculated results was verified by experimental Raman spectra of PCB77 standard. This study can elucidate further information to promote the development of Raman spectroscopy in environmental monitoring. 相似文献