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1.
Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion. 相似文献
2.
Characteristics and sources of polycyclic aromatic hydrocarbons in impervious surface run-off in an urban area in Shanghai, China 总被引：1，自引：0，他引：1
Rainwater and run-off from three kinds of impervious surface in the Shanghai urban area, China were sampled. Polycyclic aromatic hydrocarbons （PAHs） were measured in the samples, and their sources were assessed. The mean sum of the 16 PAH concentrations measured in rainwater and run-offs from ceramic tiles, asphalt roofs, and asphalt roads were 873, 1404, 1743, and 4023 ng/L, respectively. The PAH concentrations found in this study were moderate compared to PAH concentrations found in run-offs in other studies. The main PAH components in the rainwater, roof run-off, and asphalt road run-off samples were 3-ring PAHs, 3-4-ring PAHs, and 4~6-ring PAHs, respectively. Source apportionment results indicated that combustion （47.4%-55.5%） and vehicular emissions （30.5%-33.0%） were the major contributors to PAHs in roof run-off. Vehicular emissions were the most significant contributors to asphalt road run-off （47.2%）, followed by combustion （23.5%）, and petroleum （16.3%）. Vehicular emissions and coal and natural gas combustion are therefore the most significant sources of PAHs in run-off from impervious surfaces in the Shanghai urban area. 相似文献
3.
本研究采实验设计方式,初步筛选重要三卤甲烷（Trihalomethane,THM）形成控制参数,包括溴离子、加氯量/有机物、温度及反应时间,并配合净水厂实际操作状况,进行参数范围设定,再利用统计软件比较各参数对THM物种形成之影响。研究结果显示含氯较高之THM物种（氯仿及二氯-溴仿）,主要受溴离子及温度影响,其中溴离子属负效应,温度则属正效应,当低溴离子浓度存在时,其生成含氯较高之THM物种高于低溴离子浓度者。至于二溴-氯仿之形成主要受溴离子及温度影响,但两参数均属正效应。在溴仿形成之控制参数与另三种THM物种不同,主要受溴离子及加氯量/有机物含量影响,前者属正效应,后者则属负效应,当高溴离子浓度存在时,高加氯量/有机物之比值者,其生成之溴仿,小于低加氯量/有机物比值者。 相似文献
4.
In order to investigate the effects of methyl ester moiety on polycyclic aromatic hydrocarbons (PAHs) and NO x formation in biodiesel combustion, the combined models were developed based on detailed methyl butanoate (MB) oxidation model and n-butane model. Also, PAHs detailed reaction mechanism and NO x formation mechanism were added to the detailed models to form the combined models. The combined models were used to compare the combustion of n-butane and MB in a shock tube simulation to understand the effects of methyl ester moiety. The results indicated that compared with n-butane, the methyl ester moiety in MB leads to different reaction pathways, more CO and CO 2 formation and less formation of PAHs precursors such as ethylene and acetylene. In addition, a better chemical insight into the effects of methyl ester moiety on NO x formation was given, which will help to understand the combustion process of biodiesel. 相似文献
5.
以三嵌段共聚物 P123为模板,通过溶剂蒸发诱导自组装技术（EISA）,以硝酸铈和硝酸铜为原料,合成CuO/CeO2稀土复合抗菌材料,比较了无机原料摩尔比对产物微观结构和抗菌性能的影响。当CuO/CeO2比例等于0.15∶0.85时,复合材料为固溶体材料,且比表面积最大为125.7 m2·g-1,抗菌缓释时间最长达66 h以上。当氧化铜含量升高后,氧化铜从固溶体中析出,大大缩短了抗菌的缓释时间;当氧化铜含量降低时,复合材料的比表面积随之减少,影响了长效抗菌性能。 相似文献
6.
Ni-jie Jing Qin-hui Wang Yu-kun Yang Le-ming Cheng Zhong-yang Luo Ke-fa Cen 《浙江大学学报(A卷英文版)》2012,13(3):230-238
To determine the ash characteristics during fluidized bed combustion and gasification purposes, the investigation of the impacts
of chemical composition of Jincheng coal ash on the sintering temperature was conducted. A series of experiments on the sintering
behavior at 0.5 MPa was performed using the pressurized pressure-drop technique in the combustion and gasification atmospheres.
Meanwhile, the mineral transformations of sintered ash pellets were observed using X-ray diffractometer (XRD) analyzer to
better understand the experimental results. In addition, quantitative XRD and field emission scanning electron microscope/energy
dispersive X-ray spectrometer (FE-SEM/EDS) analyses of ash samples were used for clarifying the detailed ash melting mechanism.
These results show that the addition of Fe2O3 can obviously reduce the sintering temperatures under gasification atmospheres, and only affect a little the sintering temperature
under combustion atmosphere. This may be due to the presence of iron-bearing minerals, which will react with other ash compositions
to produce low-melting-point eutectics. The FE-SEM/EDS analyses of ash samples with Fe2O3 additive show consistent results with the XRD measurements. The CaO and Na2O can reduce the sintering temperatures under both the combustion and gasification atmospheres. This can be also contributed
to the formation of low-melting-point eutectics, decreasing the sintering temperature. Moreover, the fluxing minerals, such
as magnetite, anhydrite, muscovite, albite and nepheline, contribute mostly to the reduction of the sintering temperature
while the feldspar minerals, such as anorthite, gehlenite and sanidine, can react with other minerals to produce low-melting-point
eutectics, and thereby reduce the sintering temperatures. 相似文献
7.
褐煤中共伴生元素锗的提取技术 总被引：1，自引：0，他引：1
文章对褐煤共伴生元素锗采用在高温和弱还原气氛下易以低价锗氧化物和硫化物形式挥发出来,凝聚在带出物烟尘和飞灰表面上,通过收集烟尘等并对其处理可实现富集。相对于燃烧灰化法,采用低温灰化法效果更好,此方法能将有机物燃尽,简化了流程,避免了锗的损失。对于品位较低的含锗的烟尘用火法富集工艺进行富集,火法富集工艺相当于二次富集,它可使低品位含锗煤烟尘通过再次火法富集得到高品位含锗烟尘,从而实现了对褐煤共伴生稀有元素的提取,回收率为含量的90%。 相似文献
8.
朱克强 《淮南职业技术学院学报》2013,13(2):12-15
火电机组的锅炉燃烧效率及标准煤耗与煤质、发电负荷率、机组环境温度有着直接的联系,供电煤耗与煤炭发热量在一定范围内呈正相关关系;而煤炭销售收入与煤质、价格、原煤到商品煤的洗选深度即资源回收率有着直接的关联;煤炭的可售资源量与煤质又是负相关,单方追求效益的最大化都会导致整体效益的下降。 相似文献
9.
刘辉 《安徽广播电视大学学报》2012,(2):121-125
通过分析植物秸秆与煤炭燃烧特性,得出植物秸秆燃烧特性主要受本身的化学特性控制。比较了不同植物秸秆燃烧结渣特性,指出主要碱金属和氯元素对燃烧设备所产生的影响,并提出相应的解决办法。 相似文献
10.
曹承平 《淮南职业技术学院学报》2008,8(3):1-3
通过对影响煤炭自燃因素的分析,建立了采空区内遗煤自燃过程数学模型,可随时预测不同漏风强度和不同推进速度条件下,采空区遗煤自然发火的危险性,对丁集煤矿1262（1）首采面采空区遗煤自燃过程中,氧化时间、工作面推进速度对煤温的影响进行了计算机模拟,成功预报了在回采过程中采空区遗煤不自燃,确保了该工作面安全回采。 相似文献
11.
李顺文 《淮南职业技术学院学报》2009,9(2):79-81,84
龙东煤矿7135工作面是龙东煤矿一个较短的综合放顶开采工作面,该工作面断层较多,煤层自燃倾向性较高,开采该煤层发火危险性大,为了确保该工作面安全回采,必须测定煤炭低温氧化过程的基础参数与采空区遗煤氧化三带宽度,掌握该工作面开采过程中采空区煤炭氧化特点及发火的规律性,确定煤炭自燃早期预测手段,制定定综合防灭火措施,确保工作面安全回采。 相似文献
12.
为准确预测煤的自燃倾向性,在总结和分析煤自燃倾向性研究现状的基础上,选取煤的组成与结构方面的碳含量、镜质组含量、固定碳含量、比表面积、微孔占比与羟基含量6项主要影响因素建立了基于BP神经网络的煤自燃倾向性预测模型,确立了建模所需的样本,并运用Matlab软件进行网络训练并完成模型检验。将该模型应用于唐山矿9煤层、11煤层及荆各庄矿的煤自燃倾向性预测,结果显示误差均小于5%,证明基于BP神经网络的煤自燃倾向性预测模型的准确度较高,可用于工程实际。 相似文献
13.
14.
To guarantee the safety of drinking water quality after chlorination, the formation, distribution and factors influencing the concentrations of haloacetic acids (HAAs) in a water distribution system (WDS) were investigated both on a full-scale WDS (FWDS) and pilot-scale WDS (PWDS) within a city in northern China. The results of both investigations showed that trichloroacetic acid (TCAA) and dichloroacetic acid (DCAA) were the dominating types of HAAs. In the FWDS, variations in the HAA content showed negative correlations with total residual chlorine, pH and non-purgeable organic carbon (NPOC) and positive correlations with temperature and UV254. In the PWDS, the concentration of HAAs after rechlorination followed the rule of ‘first rise and then fall’; therefore, locating an appropriate rechlorination point and lowering the single chlorine dosage could be used as effective measures to control the HAA content in WDSs. 相似文献
15.
不同气氛和素坯密度对燃烧合成Ti_3AlC_2粉体的影响 总被引：1，自引：0，他引：1
实验结果表明 ,Ti:Al:C =2 :2 :1(摩尔比 )体系燃烧合成Ti3AlC2 的环境气氛若为真空 ,燃烧产物主要为TiC ,若为氩气 ,燃烧产物主晶相为Ti3AlC2 ;增加反应物原料的素坯密度 ,可较大程度地提高燃烧产物中Ti3AlC2 的含量。 相似文献
16.
Carbonaceous mesophase derived from differentpitches has different features[1—4], such as sphere sizedistribution, deformability, and solubility. For themesophase used to produce fibers, homogeneous bulkmesophase is a desirable candidate[5,6]. Thus the o… 相似文献
17.
闫维东 《宁夏师范学院学报》1999,20(3):30-33
将城区采暖期１１月份和非采暖期４月份空气中二氧化硫和氮氧化物的含量进行测定,并对数据进行统计分析研究,表明冬季取暖时,燃煤排放的废气已对大气环境造成了很大的污染,为城区的大气污染治理提供依据。 相似文献
18.
Combustion kinetic parameters (i.e., activation energy and frequency factor) of coal have been proven to relate closely to
coal properties; however, the quantitative relationship between them still requires further study. This paper adopts a support
vector regression machine (SVR) to generate the models of the non-linear relationship between combustion kinetic parameters
and coal quality. Kinetic analyses on the thermo-gravimetry (TG) data of 80 coal samples were performed to prepare training
data and testing data for the SVR. The models developed were used in the estimation of the combustion kinetic parameters of
ten testing samples. The predicted results showed that the root mean square errors (RMSEs) were 2.571 for the activation energy
and 0.565 for the frequency factor in logarithmic form, respectively. TG curves defined by predicted kinetic parameters were
fitted to the experimental data with a high degree of precision. 相似文献
19.
以SnCl4.5H2O和SbCl3乙醇溶液为原料,采用离子交换除氯水解法及正丁醇共沸蒸馏干燥法制备得到了掺锑氧化锡纳米粉末,用FT-IR、XRD和TEM等方法对粉体进行了表征。 相似文献
20.
基于煤自燃氧化特性测试系统,推导煤自燃过程中的平均耗氧速率和标准耗氧速率计算式,求解各温度点煤体的平均氧浓度数值以及氧浓度和耗氧速率分布函数,确定煤自燃氧化动力学参数表达式。采用模拟实验对此系统的耗氧规律进行分析,结果表明,煤自燃过程中随着温度升高,反应体平均氧浓度点逐渐沿气体流动方向远离流动距离中心点,各温度点煤体氧浓度及耗氧速率沿流动路径呈负指数分布,当温度较低时可近似作线性处理。此外,分析表明,若以平均耗氧速率作为煤自燃氧化反应速率,可更全面、直观地对煤自燃氧化阶段进行划分。 相似文献