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61.
Libby, Montana is the only PM2.5 nonattainment area in the western United States with the exceptions of parts of southern California. During January through
March 2005, a particulate matter (PM) sampling program was conducted within Libby’s elementary and middle schools to establish
baseline indoor PM concentrations before a wood stove change-out program is implemented over the next several years. As part
of this program, indoor concentrations of PM mass, organic carbon (OC), and elemental carbon (EC) in five different size fractions
(>2.5, 1.0–2.5, 0.5–1.0, 0.25–0.5, and <0.25 μm) were measured. Total measured PM mass concentrations were much higher inside
the elementary school, with particle size fraction (>2.5, 0.5–1.0, 0.25–0.5, and <0.25 μm) concentrations between 2 and 5
times higher when compared to the middle school. The 1.0–2.5 μm fraction had the largest difference between the two sites,
with elementary school concentrations nearly 10 times higher than the middle school values. The carbon component for the schools’
indoor PM was found to be predominantly composed of OC. Measured total OC and EC concentrations, as well as concentrations
within individual size fractions, were an average of two to five times higher at the elementary school when compared to the
middle school. For the ultrafine fraction (<0.25), EC concentrations were similar between each of the schools. Despite the
differences in concentrations between the schools at the various fraction levels, the OC/EC ratio was determined to be similar. 相似文献
62.
Effects of sewage sludge blending on the coal combustion: a thermogravimetric assessment 总被引:3,自引:0,他引:3
Combustion of urban sewage sludge together with coal in existing infrastructures may be a sustainable management option energetically interesting for these materials, usually considered wastes. Thermogravimetric analysis was used to study the combustion of a semianthracite coal and the modifications undergone when adding a small percentage (2%, 5%, 10%) of sewage sludge. Both Differential Scanning Calorimetric analysis and Differential Thermogravimetry burning profiles showed differences between coal and sewage sludge combustion. However, the effects of adding a percentage of sewage sludge equal or smaller than 10% was hardly noticeable in terms of heat release and weight loss during the coal combustion. This was further proved by non-isothermal kinetic analysis, which was used to evaluate the Arrhenius activation energy corresponding to the co-combustion of the blends. This work shows that thermogravimetric analysis may be used as an easy rapid tool to asses the co-combustion of sewage sludge together with coal. 相似文献
63.
M. Tufail Sikander M. Mirza Arif Mahmood A. A. Qureshi Yasir Arfat H. A. Khan 《Journal of environmental radioactivity》2000,50(3):283
Using the closed-can technique, radon exhalation rate measurements have been carried out for shale and coal samples collected from various mines located in the Chakwal and Makarwal areas of Pakistan. For the two areas, the measured average values of the exhalation rates from shale are 1.45±0.13 and 0.67±0.25 Bq m−2 h−1 and for coal are 1.0±0.03 and 0.65±0.32 Bq m−2 h−1, respectively. These values are much lower than the measured exhalation rates from alum-shale-based Nordic concrete which has values in the 50–200 Bq m−2 h−1 range. The lower values of the measured exhalation rates from the shale and coal deposits in the Chakwal and Makarwal areas are indicative of their lower uranium contents and mine workers in these areas do not face any abnormal health hazard due to radon since the exhalation rates have been found to be on the low side. 相似文献
64.
Mejdi Jeguirim Lionel Limousy Eric Fossard 《International Journal of Green Energy》2016,13(6):608-615
Spent coffee grounds (SCG) and coffee husks (CH) were evaluated as biofuels, after densification, for energy production. CH represent a specific problem for the coffee industry due to a low calorific value, high ash content, and a very low bulk density. Hence, the energetic potential of SCG (95 wt%)/CH (5 wt%) blend and pure SCG (100%) were examined. The blend of SCG and CH was limited to 5 wt% of CH because of the low bulk density of CH. Therefore, physicochemical and energetic characterizations of the produced pellets were performed. Thermogravimetric analyses were performed under nitrogen and air atmospheres to evaluate the CH behavior in the blend. Characterization study shows that both produced pellets could reach the French Agropellets standard (AQI). Thermal degradation showed that the mean reactivity of the SCG/HC pellets was higher than pure SCG. Then, combustion experiments were performed in a domestic combustor, after modification of the boiler power in order to improve its energetic performances. The presence of CH led to a rise of CO, NOx, VOC’s, and particle emissions. Nevertheless, the performances of the biofuels are almost in agreement the NF EN 12809 standard. 相似文献
65.
Christine Achten Fokko Tjark Beer Christian Stader Sigrid Grosse Brinkhaus 《Environmental Forensics》2015,16(1):42-50
If organic matter is burnt, the combustion of wood produces the highest amounts of polycyclic aromatic hydrocarbons (PAHs) compared with other fossil energy sources such as oil, coal, or gas. Emissions from wood combustion are increasingly of special interest due to the rising use of wood as a renewable energy source in residential heating in Europe. To the authors' knowledge, reproducible wood-specific PAH patterns in soot were identified for the first time by use of a sampling interval of only 5 min in this study. The short sampling interval was enabled by the very sensitive analytical method of gas chromatography–atmospheric pressure laser ionization–mass spectrometry (GC-APLI-MS) applied. The analysis of 40 PAH of soot from wood logs of spruce, pine, larch (softwood) and beech, birch, oak (hardwood), and wood pellets, as well as wood briquettes, showed 13.46–250.62 mg/kg for ∑40 PAH and 10.75–177.94 mg/kg for the U.S. Environmental Protection Agency PAH standard (without acenaphthylene and anthracene). Highest concentrations occurred in the samples from birch with bark, beech, and wood briquettes. Indeno[1,2,3-cd]pyrene, naphthalene, and alkylated naphthalenes were also detected. Significant concentrations of the very toxic dibenzopyrenes (up to 11.30 mg/kg) are reported. Softwood soot contained highest amounts of 2–4-ring PAH, followed by hardwood which is in accordance with the presence of highest amounts of abietic acid in softwood, a known precursor of retene and phenanthrene. PAH in soot from five spruce samples from different locations show a mean ∑40 PAH concentration of 13.46 mg/kg (n = 5, minimum 8.03, maximum 23.32 mg/kg, SD = 5.65) and exhibited a typical pattern that differed from all other wood soot samples. The distributions of alkylated naphthalenes of the spruce samples show a bell-shape distribution in contrast to the alkylated phenanthrenes/anthracenes of all samples (except the wood pellets), showing a slope distribution. The data indicate that wood-specific PAH patterns exist and under the applied conditions, spruce logs produced the least toxic soot. 相似文献
66.
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68.
介绍了熔融盐循环热载体无烟燃烧技术(nonflame combustion technology usingthermal cyclic carrier of molten salt,简称NFCT).利用沉淀法制备了Fe2O3粉末,并通过机械法加工成氧载体.XRD分析表明所制备的Fe2O3粉末为单一的α-Fe2O3相在固定床反应器中表征了氧载体得失晶格氧的过程,随循环次数的增多,氧载体被CH4还原的速率会有所增加,氧载体在CH4和空气气氛中得失晶格氧是可逆过程,反应后,氧载体内部形成了蜂窝状结构.氧载体的转化度最大为82%,占氧载体总质量18%的晶格氧可以用来氧化CH4.在熔融盐反应器中用CH4作为燃料和所制备的氧载体进行了燃料燃烧和氧载体复原的实验研究在燃料燃烧反应的开始阶段,CH4大部分被氧化成了CO2,CO2的体积分数最高可以达到85%,随着反应时间的增加,氧载体的氧化能力下降,不完全氧化产物CO和未反应的CH4的体积分数逐渐升高,3000s时,CO2的体积分数只有50%在氧载体恢复晶格氧的过程中,在1500s以前,空气中的O2都被氧载体所吸收,1500s以后,该过程排出气体中的O2体积分数开始上升,至2000s气体成分与空气的成分相同.在实验中没有检测出NOx的生成. 相似文献
69.
70.
以发电厂粉煤灰为原料,采用碱融水热法合成了HZSM-5分子筛(FHZSM-5),用浸渍法负载10%(w)CeO2制备了CeO2/FHZSM-5催化剂,用于二氯甲烷的催化燃烧.盐酸浓度为2 mol/L及粉煤灰和NaOH的质量比为1:1.2时制备的FHZSM-5纯度最高,结晶度最好,用其制备的CeO2/FHZSM-5催化剂... 相似文献