褐煤脱水及水质净化研究

为实现褐煤提质并缓解褐煤产区缺水现状,采用微波及水热脱水方法对褐煤进行脱水改性并回收褐煤所脱水分.通过检测水分化学需氧量、氨氮、总磷、硬度、离子、有机化合物等各项指标,对褐煤中水分进行深入分析,并比较两种脱水方法的脱水、净化效果.结果表明微波方式脱水率可达70%~80%,除化学需氧量外,其它水质指标均符合工业用水标准,且杂质含量随微波功率增加而降低,利于净化回收.水热方式可有效改善褐煤煤质,脱水率最高可达87.44%,但各项水质指标均大大超出标准范围,且杂质含量在250℃工况下达到最大.两种冷凝水均检测到微量有毒金属元素、有毒致癌的多环芳烃及酚类化合物,将成为后续净化的主要脱除对象.     

Effect of oxidation treatment on the adsorption and the stability of mercury on activated carbon

Oxidation treatment on the adsorption and the stability of Hg on activated carbon （AC） was inrestigated. Both MnO2-AC and FeCl3-AC were produced during oxidation treatment. The measurement of modified AC＇s mercury adsorption capacity was conducted in a simulated coal-fired flue gas by adsorbing test apparatus. TCLP and column leaching methods were used to test the stability of mercury adsorbed on ACs. The results indicate that the oxidation treatment changed the pore structure of the AC and modified the carbon surface by creating chemical components such as MnO4^-, Mn^4＋, O, NO^3-, Fe^3＋, Cl^-, etc. The Hg sorption capacity on MnO2-AC or FeCl3-AC was about three times higher than that of untreated carbon. In addition, the mercury control cost of each of the formers was about the half cost of the untreated carbon. The stability of Hg absorption was studied, it found that mercury adsorbed on the oxidation treated AC was not better than that of untreated carbon. It could concluded that the insoluble form of Hg is very important to the stability of mercury adsorbed on AC. This study suggests that the FeCl3-AC is the best absorbent for Hg with high adsorption capacity, better Hg adsorption stability in leaching environment, and lower cost among the three ACs tested.     

纤维素热裂解的二次反应研究

在热重红外联用分析仪上开展了纤维素的热裂解失重研究,通过对纤维素热裂解的TG和DTG曲线以及热解产物的红外析出图谱的分析研究,探讨了纤维素热裂解的二次反应过程及机理,并在经典Broido—Shafizdeh模型的基础上．提出了改进的纤维素热裂解模型。     

秸秆还田对水稻镉积累及其亚细胞分布的影响

镉(Cd)是人类一级致癌物,大米食用是以大米为主食人群摄入Cd的主要途径.秸秆还田是秸秆处理中主要方式,在Cd污染稻田被广泛应用,其对水稻Cd吸收及水稻体内Cd的分布产生的影响不可忽视.本研究选用Cd水稻土,通过盆栽和大田试验分析了不同的秸秆还田用量(0.0%、1.0%、2.5%和5.0%)对Cd的亚细胞分布以及在水稻籽粒中积累的影响.结果表明水稻根细胞中的Cd主要分布在细胞壁中,占总Cd的86%~95%,茎叶细胞的细胞壁与可溶部分中的Cd含量相当,分别占总Cd的30%~51%和35%~61%.秸秆按1%和2.5%比例还田能显著提高根中Cd含量,以及细胞壁中Cd含量及其分配比例,并降低水稻体内Cd由根向茎叶转运;但5%的秸秆还田,分蘖期根中Cd含量和细胞壁中Cd含量显著降低,Cd由根向茎叶转运系数提高,灌浆期的根中Cd含量和细胞壁中Cd含量均显著提高,转运系数没有显著变化.大田试验前茬的水稻秸秆和油菜秸秆中Cd含量均较高,分别是0.49 mg·kg~(-1)和0.67 mg·kg~(-1);油菜秸秆单独还田或与石灰一起还田均没有显著影响水稻糙米或秸秆中Cd的积累;水稻秸秆单独还田也没有显著改变水稻糙米或秸秆中Cd的积累,但与石灰一起还田时能显著降低糙米和秸秆中的Cd积累;生物炭添加能显著降低水稻体内的Cd积累,且与石灰一起添加降Cd效果更显著.因此,当用Cd污染稻田前茬所产水稻秸秆还田时,建议与石灰一起添加可达到显著降Cd的效果.该研究将为Cd污染稻田的水稻安全生产与秸秆循环利用提供理论与实践指导.     

Laboratory-scale study of the suppression of PCDD/F emission during coal and MSW co-incineration

The experimental test of co-incinerating Chinese raw municipal solid waste （MSW） and coal in a laboratory-scale tubular reactor was first reported in present study, and the emission of normal gas components and the effects of the S/Cl molar ratio or coal mixing percentages on polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDDs/Fs） emission were investigated and discussed. The results indicated that OCDD was the only PCDD homologues since others like TCDD-HpCDD was hardly detected, while as the categories of PCDF homologues were comparatively much more general. The amount of PCDD was much larger than that of PCDF in all operating conditions. Since ZPCDF/∑PCDD〈〈1, the dominant role of the precursor formation was proven in our experimental conductions. With increasing the coal addition to MSW （from 0 to 16%）, PCDD and PCDF were reduced considerably. Coal and MSW may suppress the PCDD/F emissions efficiently （over 95%） during the MSW incineration process. The PCDD/F suppression results of the present study could be helpful guidance to the industrial application of Chinese MSW and auxiliary coal co-incineration processes. The PCDD/F stack emission data of two industrial incinerators using co-incineration technology in China seem to have a great positive reduction of PCDDs/Fs.     

废轮胎流化床热解半焦结构特性

以流化床反应器为主体对废轮胎热解半焦微观结构特性进行了研究.主要研究了热解温度、床料粒径、流化数等参数对热解半焦的比表面积、孔隙率、孔体积的影响.结果表明:半焦比表面积和孔隙率随温度变化过程中会在650℃或750℃出现一峰值,这表明对半焦品质而言,轮胎存在最佳的热解温度,采用较小粒径(0.135～0.304mm)床料时有使最佳热解温度下降的趋势;半焦孔隙率随流化数增加而减小;半焦比表面积随流化数的变化趋势与热解温度有关,550℃时流化数增加半焦比表面积减小,650℃时流化数增加半焦比表面积增大;半焦孔体积随温度的变化趋势与床料粒径有关,采用较大粒径(0.304～0.4mm)床料时,半焦孔体积随温度升高呈现先降后升的趋势,而采用较小粒径(0.135～0.304mm)床料时,半焦孔体积随温度升高呈现下降的趋势.     

突发性大气污染监测与预报技术集成移动平台

为应对突发性大气污染事故科学决策和规范处置的需要,在国家“863”课题“突发性大气污染事件模拟与风险控制技术”资助下,我国首个突发性大气污染监测与预报技术集成(IMF)移动平台研发成功.2010年7月5日至8月6日在北京市阳坊地区的综合外场实验表明, IMF移动平台从燃油燃烧事故监测至应急预案发布需时约5min.采用逐次偏差订正法,有效改进了气象预报场,实验中近地面黑碳预报最大浓度较合理.     

萃取在含盐有机废水焚烧处理中的应用

提出并研究了萃取-焚烧工艺在蒸发残液焚烧处理中的应用.以乙酸乙酯为萃取剂,水油体积比为5时,将含30 g·L-1氯化钠、1 g·L-1对硝基苯酚的模拟废水剧烈振荡1min,静置10 min后进行萃取,一级萃取效率和二级萃取效率分别为97.12%和99.89%.随着水油比的升高,一级萃取效率和二级萃取效率都有所下降,但是经过二级萃取之后,有机物的萃取率均在99.00%以上.废水中的氯化钠对萃取效率有提高作用,当氯化钠浓度从60g·L-1升高到200 g·L-1时,一级萃取效率和二级萃取效率分别从94.76%和99.82%上升到97.53%和99.92%.正辛醇的萃取效率较乙酸乙酯低.经过萃取脱盐的有机相,蒸发回收有机溶剂后得到有机物残渣,有机物残渣与有机废水蒸汽一起进入流化床焚烧炉进行焚烧处理;当焚烧炉的温度从700℃提高到850℃时,有机废水蒸汽单独焚烧的焚烧效率从86.34%上升到99.96%,而有机废水蒸汽和有机残渣混合焚烧时的焚烧效率则从90.16%上升到99.99%.     

我国城市街尘重金属污染研究进展与趋势

国外城市街尘重金属污染研究较早,国内相关研究虽起步较晚,但发展迅速。本文搜集了近10a来中国城市街尘重金属污染研究的主要成果,从重金属含量、空间分布特征、赋存形态、污染来源以及污染影响评价等方面进行详细梳理,并就未来我国城市街尘重金属污染研究的发展趋势提出了一些建议。     

煤中挥发氮析出过程模拟:不同热解模型的影响

采用数值模型研究了煤热解、燃烧过程中挥发分氮的析出、中间含氮产物HCN的生成以及转变为NO的过程．分别采用双方程模型和通用模型描述热解过程，利用有限体积方法对质量、化学组分、动量和热量守恒方程进行离散求解．计算结果表明两种模型获得的热解过程、孔隙率、HCN生成率等方面存在一定差别，而对颗粒着火时间、NO生成率等方面比较接近．与试验结果比较，采用双方程模型对模拟烟煤颗粒的挥发氮析出过程准确度相对较高．