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采用燃料氧燃烧直接供热的氧化钙-二氧化碳双床循环系统已经被研究开发,用于从电厂尾气中脱碳。本研究基于实验和化学反应工程原理建立了分析模型,用于系统地研究循环特征,氧化钙活性衰减,燃料及其炉内热利用率的影响。基于模型推导获得了重要参数:最小循环热损失和最小热需求量,以及对应的固体循环比。它们都受供热燃料灰分和含硫量的影响,也受脱碳率的影响。显然最佳固体循环比介于二者之间。另一个重要参数是燃料在炉内的热利用率。高的热利用率不仅降低燃料需求量,降低其灰分和含硫的影响,降低氧的需求量及其辅助功,而且提高蒸汽循环的发电效率。一个发现是热需求量在临界固体循环比接近无穷大,这就限制了固体循环比的可操作范围, 以及燃料的灰分和含硫量。建立的分析模型和推导直接提供了这些变量之间的关系和范围。 相似文献
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R. Kötz 《Electrochimica acta》1984,29(11):1607-1612
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以ZrO2为载体,制备出TiO2-SiO2/ZrO2催化剂,用XRD和SEM对其进行表征;并将催化剂用于甲苯的催化燃烧,探讨了温度、气流速率、进气浓度等因素对甲苯催化效率和反应产物CO、CO2选择性的影响。结果表明:催化剂中的TiO2呈锐钛矿晶型,催化剂颗粒成功负载于ZrO2表面;随着温度升高,甲苯催化效率增大,350℃时能达到最大值100%,CO2选择性随之增大,但CO选择性却减少;气流速率增大导致甲苯催化效率增大,CO选择性稍稍增大,而CO2选择性减小;进气浓度从25 mg/L增加到100 mg/L时,甲苯催化效率逐渐减小,CO2选择性减小,CO选择性稍有增大。 相似文献
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采用自制的纳米TiO2粉体作光催化剂,以甲基橙模拟有机污染物,研究了光照时间、催化剂用量、被降解物浓度、系统酸度等对其光催化性能的影响。结果表明:降解某一物质时,不同光催化剂,有一个降解速率最大的时间;在每一个降解的过程中催化剂有一个合适的用量;在弱酸性条件(pH=3),甲基橙降解效果比较好;被降解物的浓度选取合适,降解率最高。 相似文献
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Wei Zhou Xiaoxiao Meng Liang Xie Junfeng Li Yani Ding Yanlin Su Jihui Gao Guangbo Zhao 《中国化学工程学报》2022,44(4):363-368
The Electro-Fenton (EF) process is one of the promising advanced oxidation processes (AOPs) for environmental remediation. The H2O2 yield of EF process largely determines its performance on organic pollutants degradation. Conventional Pd-catalytic EF process generates H2O2 via the combination reaction of anodic O2 and cathodic H2. However, the relatively expensive catalyst limits its application. Herein, a hybrid Pd/activated carbon (Pd/AC)-stainless steel mesh (SS) cathode (PACSS) was proposed, which enables more efficient H2O2 generation. It utilizes AC, the support of Pd catalyst, as part of cathode for H2O2 generation via 2-electron anodic O2 reduction, and SS serve as a current distributor. Moreover, H2O2 could be catalytically decomposed upon AC to generate highly reactive ·OH, which avoids the use of Fe2+. Compared with conventional Pd catalyst, H2O2 concentration obtained by PACSS cathode is 248.2% higher, the O2 utilization efficiency was also increased from 3.2% to 10.8%. Within 50 min, 26.3%, 72.5%, and 94.0% H2O2 was decomposed by Pd, AC, and Pd/AC. Fluorescence detection results implied that Pd/AC is effective upon H2O2 activation for OH generation. Finally, iron-free EF process enabled by PACSS cathode was examined to be effective for reactive blue 19 (RB19) degradation. After continuous running for 10 cycles (500 min), the PACSS cathode was still stable for H2O2 generation, H2O2 activation, and RB19 degradation, showing its potential application for organic pollutants degradation without increase in the running cost. 相似文献
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用于化妆品的SiO2/TiO2复合微球的制备及表征 总被引:3,自引:0,他引:3
通过溶胶凝胶法在微米级的二氧化硅(SiO2)微球上包覆一层纳米级的二氧化钛(TiO2)粒子,将制备出的复合微粒表面接枝聚合改性,改性前后的复合颗粒用FT-IR、XRD表征,并用扫描电镜观察了微粒的形貌,用紫外分光光度计扫描了添加改性后复合微粒的自制防晒液的紫外吸收谱图,发现经复合后的纳米TiO2粒子的分散性能得到明显改善,复合处理后TiO2粒子的紫外吸收能力较纯TiO2增强80%,且光催化能力得到很大抑制,TiO2作为防晒剂安全性能大大提高,并讨论了该复合粒子在化妆品中的应用。 相似文献
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引言过氧化氢(H2O2)是一种理想的绿色氧化剂,广泛应用于化学品合成、纺织、造纸、环保、食品、医药、冶金和农业等领域[1]。目前,蒽醌法[2-5]是工业上生产H2O2的主要方法。20世纪40年代,德国I.G.Farbenindustrie首先采用蒽醌法(又称Riedl-Pfleiderer法)工业化生产过氧化氢。该方法首先将2-烷基蒽醌(通常是2-乙基蒽醌)溶解于合适的有机溶剂中,溶液中的2-烷基蒽醌经催化剂催化加氢,被还原成蒽氢醌或5,6,7,8-四氢蒽氢醌,再经空气氧化得到蒽醌或四氢蒽醌和 相似文献
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报道了用笑气-乙炔火焰原子吸收光谱法测定氟石中氧化铝。试样经氢氟酸处理、高氯酸冒烟后,加入盐酸和硼酸温热溶解残渣。用富燃笑气乙炔焰在分析线A1309.3 nm处,测定铝的吸光度。试验了溶样酸和酸度、硼酸、基体钙及共存元素对测定的影响。校准用的标准溶液系列中加入相同量的钙和硼酸作基体匹配。方法回收率96%~105%。本方法准确度、精密度满足商品检验的要求,已用于出口氟石的检验。 相似文献
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《Carbon》2013
A series of carbide-derived carbons (CDC) have been prepared starting from TiC and using different chlorine treatment temperatures (500–1200 °C). Contrary to N2 adsorption measurements at −196 °C, CO2 adsorption measurements at room temperature and high pressure (up to 1 MPa) together with immersion calorimetry measurements into dichloromethane suggest that the synthesized CDC exhibit a similar porous structure, in terms of narrow pore volume, independently of the temperature of the reactive extraction treatment used (samples synthesized below 1000 °C). Apparently, these carbide-derived carbons exhibit narrow constrictions were CO2 adsorption under standard conditions (0 °C and atmospheric pressure) is kinetically restricted. The same accounts for a slightly larger molecule as N2 at a lower adsorption temperature (−196 °C), i.e. textural parameters obtained from N2 adsorption measurements on CDC must be underestimated. Furthermore, here we show experimentally that nitrogen exhibits an unusual behavior, poor affinity, on these carbide-derived carbons. CH4 with a slightly larger diameter (0.39 nm) is able to partially access the inner porous structure whereas N2, with a slightly smaller diameter (0.36 nm), does not. Consequently, these CDC can be envisaged as excellent sorbent for selective CO2 capture in flue-gas streams. 相似文献
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Bo Wang Rong Hu Jun Zhang Zongyu Huang Hui Qiao Lunjun Gong Xiang Qi 《Journal of the American Ceramic Society》2020,103(2):1088-1096
Two-dimensional (2D) SnS2/MoS2 heterojunction with a 2D/2D novel structure was used as electrode material for enhanced supercapacitor performance. Compared with the sole SnS2, the as-prepared 2D/2D SnS2/MoS2 layered heterojunction has exhibited great improvement in supercapacitor properties. This novel structure can effectively prevent agglomeration and stacking in electrochemical process, and 2D/2D structure is beneficial to intercalation and desorption of ions in electrochemical processes. The experiment result shows that MoSn5 (samples with 5% MoSn5 mole ratios) display a specific capacitance of 466.6 F/g at the current density of 1 A/g in 0.5 mol/L potassium hydroxide solution, an impressive cycling stability with 88.2% capacitance retention at current density of 4 A/g. In addition, the as-fabricated symmetric supercapacitor exhibited high energy density of 115 Wh kg−1 at the power density of 2230 Wh kg−1. This work provides a fundamental investigation of 2D/2D layered material synergistic effect on the electrochemical process. 相似文献