Environmental and safety aspects of seasonal storage of baled municipal solid waste to be used as fuel for energy production (waste fuel), was investigated and experiments were carried out on burning of bales. The flammability, combustion processes and emissions were studied by simulating, in small-scale, potential effects of a possible fire in full-scale bale storage area. Despite the high water content and the high density of the bales, after setting fire, the bales burned well, even though no risk for self-ignition exists. The following parameters of the combustion product were measured continuously: O2, CO2, CO, SO2, NO, NO2, NOx, THC, smoke gas rate and the temperature of the smoke. Soot particles in the smoke were collected and analysed for Hg, Pb, Cd, As, Ni, Cr, Mn, Cu, Co, Sb and V concentrations. The analysis of the moisture content, concentrations of Hg, Cd, HCl, HF, HBr, NH3, polyaromatic hydrocarbons (PAH), chlorinated and brominated dioxins (PCDD/F and PBrDD/F, respectively) were carried out. It was found that the PCDD/F levels (TEQs) varied according to the system used: 12.53 ng (I-TEF-88)/Nm3; 14.09 ng (I-TEF-99)/Nm3; 13.86 ng (Eadons)/Nm3. The PAH concentration was 3.04 microg/Nm3. The contents of the metals in the smoke (with the exceptions of Pb and Cd with mean values of 1.74 and 0.36 mg/m3, respectively) were below the limit values established by the Swedish Ministry of Environment for emissions from incineration plants [Swedish Ministry of Environment, (2002:1060), F?rordning 2002:1060 om avfallsf?rbr?nning. Available from http://www.notisum.se/rnp/SLS/LAG/20021060.HTM]/EU-directive [(2000/76/EC), Directive 2000/76/EC, of the European Parliament and of the Council of 4 December 2000 on the Incineration of Waste. http://www.Scotland. gov.uk/library5/environment/iecda.pdf]. The HCl concentration was 10 times higher than the limit value (mean value of 99 mg/m3). 相似文献
The electrodes in industrial precipitators collect many tons of dust daily, and the efficient transfer of this dust burden to the hoppers is a challenging problem in mechanical engineering. Many varieties of devices have been tried; hammers, vibrators, scrapers, water flushing, gas blasting, etc. Impact devices for this purpose are usually called “rappers.” Laboratory experiments described in this paper show that normal (perpendicular) rapping is more effective than shear rapping; that thick dust layers are more easily removed by rapping than thin ones; that rapping becomes easier with increasing temperature, within limits; and that the electrostatic forces acting upon the precipitated dust layer play an important role. Quantitative data are shown graphically. The relation of these results to previous studies by other investigators is discussed. 相似文献
This paper presents a methodological approach for the study of volatile organic compounds (VOCs) in air, emitted during storage of municipal solid waste in bales. Determination of VOCs was based on sampling with adsorbent tubes followed by automated analysis using on-line work-up with a thermal desorption unit directly connected to a gas chromatograph-mass spectrometer. Using calculation algorithms and multidimensional statistical analysis of large amounts of data collected, the information was compressed and visualized. The approach was applied to initial measurements of emissions of VOCs from 24 bales composed of municipal solid waste, each bale stored in a wooden box. These bales were produced using the two types of baling equipment available, resulting in cylindrical or rectangular bales, with different densities. Hundreds of different VOCs emitted from these bales sorted out into groups with different chemical structure. Differences in VOC concentrations in air were found between wastes stored in cylindrical or rectangular bales. For instance, it was found that the concentration of VOCs (relative to the concentration of toluene), in the first experiment after storing, for cylindrical bales with six layers of LDPE was 115 +/- 10 microg m(-3), while for rectangular bales it was only 64 +/- 8 microg m(-3). The procedure used for data interpretation suggested different degradation mechanisms in different types of bales. The use of multiple data interfaces, multidimensional statistics and automated chemical analysis methods are likely to be more and more common for waste companies and waste research in the near future. This is due to the interdisciplinary nature of the subject that relies heavily on various areas of science and information technology. 相似文献
This paper focuses on the volatile organic compound emissions from baled municipal solid waste (MSW). The analytical methodology was based on sampling with adsorbent tubes once a month during seven occasions within a time period of 1 year. Automated analyses were carried out on-line work-up with thermal desorption directly connected to a gas chromatograph-mass spectrometer. The effect of different baling techniques, cylindrical and rectangular baling was compared. It was found that cylindrically baled MSW emitted larger concentration of esters than their rectangular counter parts. Conversely, aromatic compounds emissions dominated in rectangularly baled MSW. This indicates that different degradation mechanisms operate in the waste bales. Cylindrical and rectangular bales are generally wrapped with six layers of 250 microm thick low density polyethylene (LDPE). It was observed that by wrapping an extra six layers of LDPE film onto the bales, the emissions from cylindrical bales increased while emissions from the rectangular counterpart decreased. Over time, the volatile organic compound emissions from cylindrical bales decreased two orders of magnitudes from 96.2 +/- 20.8 microg m(-3) in September 2003 to 0.80 +/- 0.07 microg m(-3) in July 2004. The rectangular bales exhibited an almost identical relative emission reduction from 54.4 +/- 4.3 microg m(-3) in September 2003 to 0.46 +/- 0.02 microg m(-3) in July 2004. Future work will concentrate on full-scale storages, taking into account waste type, storage size, temperature development and the different baling techniques among other variables. 相似文献