烟气脱硫渣-Mn3O4混合氧载体与煤反应特性研究

基于TG-FTIR联用技术,结合SEM-EDX、XRD和XPS等表征手段,深入研究了煤与烟气脱硫渣制备的CaSO_4-Mn_3O_4混合氧载体的反应特性,重点关注Mn_3O_4对CaSO_4反应活性的提升及其对CaSO_4副反应过程气相硫释放的抑制,发现CaSO_4-Mn_3O_4氧载体与煤反应时,通过独特的氧传递特性和利用途径,不仅实现了 CaSO_4中晶格氧的充分利用、促进煤的高效转化和CO_2的有效捕集,还能够抑制并定向脱除CaSO_4副反应释放的SO_2。最后,热力学模拟发现,在优化反应条件下,SO_2的排放比例不高于1%,相比于不加Mn_3O_4时的2.4%,在抑制和捕集SO_2方面具有显著提高。     

超临界CO2-DME混合物竖直圆管内传热特性数值研究

本文采用RNG k-ε湍流模型对超临界CO₂/DME(二甲醚)二元混合工质在竖直圆管内的传热特性进行了数值模拟研究。管径4 mm,管长为1000 mm;CO₂/DME浓度配比分别为97/3、95/5、92/8、90/10、85/15、以及70/30;质量流速为125~200 kg·m^-2.s^-1;热流密度为15~30 kW.m^-2,入口温度295~308 K,入口压力8~15 MPa。不同浓度配比的混合工质在各自临界压力下应用时,随着DME浓度的增加,换热系数的峰值逐渐减低,但在温度大于310 K时混合工质的换热系数会高于纯CO₂。压力相同时,随着DME浓度的增大,拟临界温度升高,换热系数峰值点也随之向温度升高的方向移动。混合工质的换热系数随质量流速的增大而增大。在拟临界点前,增大热流密度及降低压力对管内传热有利,而在拟临界点之后,换热系数随热流密度的升高以及压力的降低而降低。     

线性映射的值域与核的结构定理及其应用

本文利用同构关系与解析方法研究了值域与核的基和维数,弄清了值域与核的几何结构,通常的维数公式是其推论,然后列举若干例子阐明其应用.     

地表高程对大气CO2反演的影响

从大气辐射传输模型正演和反演两个角度,探究CO_2观测时地表高程的敏感性。SRTM地表高程数据表明,在北京附近的平原地区,卫星指向不准导致的地表高程均值的误差较小,在偏移量为0.1～10.0km的情况下,误差极大值约为10m;而在北京附近山区以及平原与山区交界区内,地表高程均值的误差较大,误差极大值分别为713.98,515.61m。CO_2反演结果表明:高程值每变化100m,CO_2柱浓度偏差为3.29×10~(-6);在大气CO_2高精度反演中,地表高程偏差是一个关键因素。     

乘积G-空间中周期跟踪性和等度连续的研究

介绍了拓扑群作用下乘积空间中G-周期跟踪性和G-等度连续的概念,利用乘积映射的性质,研究了乘积映射f×g与分映射f和g在这些动力学性质方面的关系,得到如下结果:1)乘积映射f×g具有G-周期跟踪性当且仅当f具有G_1-周期跟踪性,g具有G_2-周期跟踪性;2)乘积映射f×g具有G-等度连续当且仅当f具有G_1-等度连续,g具有G_2-等度连续.这些结论弥补了拓扑群作用下乘积空间中G-周期跟踪性和G-等度连续理论的缺失.     

改性多孔CO2吸附剂的研究进展

由温室效应带来的全球变暖等一系列环境危害已受到越来越多的关注,CO2是对温室效应贡献最大的气体且用途广泛,因此,其控制减排及再利用尤为重要.综述了近年被广泛研究的CO2多孔吸附剂的发展状况,详尽阐述了沸石、多孔炭、有机金属骨架(MOFs)和多种介孔吸附剂的优缺点及其改性方法,同时比较了这几种多孔吸附剂改性前后的特性及其对CO2的吸附效果.并且展望了CO2吸附剂的发展前景,为新型高效CO2吸附剂的研发提供了参考.     

IPDA激光雷达数据反演快速精确优化算法

研究了积分路径差分吸收(IPDA)激光雷达中采用洛伦兹线型代替伏格特线型对机载平台探测CO₂柱浓度精度的影响。建立仿真模型，讨论两种线型在数据反演中对温度和气压的敏感性，以及探测相对误差变化随飞行高度的变化。结果表明：伏格特和洛伦兹线型得到的吸收截面，温度和气压敏感性，相对随机误差分别为0.860%，-0.703%和0.224%，基本没有差别，但是洛伦兹线型可以有效地提高光谱参数计算效率。机载IPDA激光雷达采用洛伦兹线型可以快速高精度反演飞行路径上CO₂柱浓度，降低了对系统计算能力的要求，有助于实现在飞期间数据实时反演和分析，以及实施针对突发事件的飞行规划，同时也有助于进一步实现机载激光雷达系统的小型化和集成化。     

一种CO2的矿化封存新方法

针对目前CO2矿化封存的研究现状,提出了一种新的CO2矿化封存方法:利用CO2和NH3反应生成三聚氰酸固体,并考察了温度、压力、反应物配比及有无催化剂对三聚氰酸收率的影响。当反应条件为在250℃,22MPa,NH3与CO2反应配比为1∶1.4,反应8h时,最高收率可达到68.3%。此项技术能够与现在工业成熟的富氧燃烧技术联用,实现对CO2的永久性封存,具有经济效益。     

Investigation of CO and formaldehyde oxidation over mesoporous Ag/Co3O4 catalysts

CO and formaldehyde(HCHO)oxidation reactions were investigated over mesoporous Ag/Co3O4 catalysts prepared by one-pot(OP)and impregnation(IM)methods.It was found that the one-pot method was superior to the impregnation method for synthesizing Ag/Co3O4 catalysts with high activity for both reactions.It was also found that the catalytic behavior of mesoporous Co3O4 and Ag/Co3O4 catalysts for the both reactions was different.And the addition of silver on mesoporous Co3O4 did not always enhance the catalytic activity of final catalyst for CO oxidation at room temperature(20 C),but could significantly improve the catalytic activity of final catalyst for HCHO oxidation at low temperature(90 C).The high surface area,uniform pore structure and the pretty good dispersion degree of the silver particle should be responsible for the excellent low-temperature CO oxidation activity.However,for HCHO oxidation,the addition of silver played an important role in the activity enhancement.And the silver particle size and the reducibility of Co3O4 should be indispensable for the high activity of HCHO oxidation at low temperature.     

Ni/Al2O3 catalysts for CO methanation: Effect of Al2O3 supports calcined at different temperatures

The correlation between phase structures and surface acidity of Al2O3 supports calcined at different temperatures and the catalytic performance of Ni/Al2O3 catalysts in the production of synthetic natural gas(SNG) via CO methanation was systematically investigated. A series of 10 wt% NiO/Al2O3 catalysts were prepared by the conventional impregnation method, and the phase structures and surface acidity of Al2O3 supports were adjusted by calcining the commercial γ-Al2O3 at different temperatures(600–1200 C). CO methanation reaction was carried out in the temperature range of 300–600 C at different weight hourly space velocities(WHSV = 30000 and 120000 mL·g-1h-1) and pressures(0.1 and 3.0 MPa). It was found that high calcination temperature not only led to the growth in Ni particle size, but also weakened the interaction between Ni nanoparticles and Al2O3 supports due to the rapid decrease of the specific surface area and acidity of Al2O3 supports. Interestingly, Ni catalysts supported on Al2O3 calcined at 1200 C(Ni/Al2O3-1200) exhibited the best catalytic activity for CO methanation under different reaction conditions. Lifetime reaction tests also indicated that Ni/Al2O3-1200 was the most active and stable catalyst compared with the other three catalysts, whose supports were calcined at lower temperatures(600, 800 and 1000 C). These findings would therefore be helpful to develop Ni/Al2O3 methanation catalyst for SNG production.