Cinétique de dégagement des matières volatiles lors de la pyrolyse d'électrodes de carbone industrielles

In aluminium plants, the anode baking process is associated with an important release of volatile combustible matter. It is the purpose of this study to investigate the kinetics of the evolution of these volatiles. A large thermogravimetry set-up has been designed in such a way that it could simulate real plant conditions. Samples of two distinct masses have been subjected to pyrolysis at different heating regimes. The loss of weight together with the concentrations of the released gases were recorded on a continuous basis during the temperature rise. Kinetic results were found for methane, hydrogen and tar. No variation of the order of reaction with the heating rate was observed, whereas the activation energy and the pre-exponential factor increased. Furthermore, for the range of sample dimensions studied, it was found that the mass of the solid had no significant influence on the kinetic parameters.     

柴油替代燃料二甲醚的应用开发和发展概况

详细介绍了二甲醚作为柴油替代燃料的开发和应用情况。以天然气为原料制二甲醚，天然气价格对产品成本影响非常大，目前二甲醚作为柴油替代燃料还不具备和柴油竞争的优势，相比之下合成气一步法工艺技术更具有竞争优势。概述了我国二甲醚发展现状，并对我国二甲醚发展提出了建议。     

Sludge Pre-Treatment through Ozone Application: Alternative Sludge Reuse Possibilities for Recirculating Aquaculture System Optimization

Recirculating Aquaculture Systems (RAS) reduce water consumption by efficient filtration to maintain appropriate levels of accumulating compounds and sludge. Sludge is mechanically separated by drum filters and disposed of to the detriment of overall system water budgets. Dissolved nitrogen compounds are reduced via nitrification–denitrification filters, requiring commercial external carbon sources. The reuse of sludge after ozone pre-treatment may represent the next step in RAS optimization. The present study analyzes the content of sludge from RAS and tests ozonation as a pre-treatment for recycling as carbon source. The dissociative effect of ozone and the physicochemical changes due to ozonation lead to a significant increase in soluble carbon availability. Predominantly long-chain fatty acid (FA) (saturated and unsaturated) with 16 and 18 carbon atoms independently of the treatment were found in the profiles. Saturated FA concentrations in solution increased after 20, 40, and 60 min ozonation. The solid content of the sludge was practically unaffected by ozonation in terms of FA profile: only saturated FA slightly increases after 40 min treatment. The implications of these findings for denitrifying bacteria are discussed.

Abbreviations: Recirculating Aquaculture Systems (RAS); Advanced Oxidation Processes (AOPs)     

Transient testing of soy methyl ester fuels in an indirect injection,compression ignition engine

An evaluation of the exhaust emissions from a compression ignition engine for fuels composed of 100 and 30% methyl esters of soy oil (SME) is described. These fuels were compared with a low-sulfur, petroleum #2 diesel fuel in a Caterpillar 3304, prechamber, 75 kW diesel engine, operated over heavy- and light-duty transient test cycles developed by the United States Bureau of Mines. More than 60 h of testing was performed on each fuel. The objective was to determine the influence of the fuels upon diesel particulate matter (DPM) and gaseous emissions. The effect of a modern diesel oxidation catalyst (DOC) also was determined in an effort to minimize emissions. Neat SME produced a higher volatile fraction of the DPM, but much less carbon soot fraction, leading to overall DPM reductions of 23 to 30% for the light- and heavy-duty transients. The DOC further reduced the volatile fraction and the total DPM. The SME fuel reduced gaseous emissions of CO by 23% and hydrocarbons by over 30% without increasing NO_x. The DOC further reduced CO and hydrocarbon levels. Mutagenicity of the SME exhaust was low. Results indicate that SME fuel, used with a proper DOC, may be a feasible emission reduction technology for underground mines. References to specific products do not imply endorsement by the U.S. Bureau of Mines, a now defunct agency.     

酸性离子液体和Na2WO4·2H2O催化

以酸性离子液体和Na₂WO₄·2H₂O组成的体系为催化剂，过氧化氢为氧化剂，将催化柴油中的噻吩硫氧化为砜类物质，并通过NMP将其萃取出来，同时考察了反应温度、反应时间和催化剂用量等因素对氧化脱硫反应的影响，得出最佳反应条件为：3 mL油样（含硫200 μg·g^_-1），1 g离子液体，0.021 g 钨酸钠（Na₂WO₄·2H₂O）， 0.7 mL过氧化氢，反应温度323 K，反应时间3 h，萃取剂与柴油体积比为1∶1，此时样品中的硫可降低到23 μg·g^-1。反应结束后，可以通过简单的倾倒将油样和催化剂分离，催化剂重复使用5次，催化活性基本不变。     

国外柴油车减少排放污染的发展趋势

叙述了美国和欧共体柴油车排放法规和最新发展及世界主要固定柴油质量和规格的最新发展趋势，报道了柴油组成和性质对排放物影响的主要研究结果；分析了减少柴油车排放污染的主要措施，例如改进发动机、改进炼油工艺、采用尾气处理、采用颗粒物过滤－捕集器及采用减少尾气排污的三类柴油添加剂，最后提出了几点建议。     

基于物元分析法的水资源管理现代化评价

为科学合理地评价区域水资源管理现代化水平,从水资源保障、用水效率、水资源保护、水资源公共管理能力、水资源支撑能力5个方面构建评价指标体系,将模糊层次分析法(FAHP)和熵权法耦合,确定评价指标综合权重,基于物元理论建立水资源管理现代化评价模型。以南京市高淳区为例进行评价,结果表明,南京市高淳区水资源现代化管理水平处于初等现代化阶段,与实际情况相符,验证了所构建评价模型的可行性和有效性。     

非临氢降凝催化剂的研制与评价

以ZSM-5为主体，加入一定量的自制BCM沸石，采用水热合成法合成新型非临氢降凝催化剂。以催化裂化柴油和减一线馏分油为原料对其反应性能进行评价。结果表明, 该催化剂具有明显的降凝效果。当反应温度为340 ℃、空速为1 h^-1时，凝点降幅为45 ℃左右，液体产品收率均在95%以上。所生产的柴油十六烷值高，硫、氮含量低，凝点低，基本满足了产品调合出厂的质量要求。     

影响消毒剂百菌灭有效成分的因素分析

探讨外部环境条件对消毒剂百菌灭产品有效成分的影响因素,测定产品在不同条件下有效成分的含量变化,实验结果表明,加入5滴肥皂水、10%血清、自来水稀释、含20%填料包装瓶,百菌灭样品活性降解率分别为51.7%、93.6%、23.86%、60.47%,而对比组其活性降解率分别为0.66%、0.66%、1.32%、48.58%,分析了阴离子化合物、有机物、水质、塑料瓶包装等因素造成百菌灭活性物含量降低的原因,提出优化生产条件和改进贮藏方法。     

基于组合赋权的湖泊健康评价物元分析模型

湖泊生态系统的健康是人与自然和谐相处及可持续发展理念的重要体现。通过建立湖泊健康评价物元分析模型,并改进其指标权重的计算,以离差平方和准则将层次分析法、熵值法及主成分分析法3种赋权方法取得的权重结合得到最优组合赋权,应用到某地5个湖泊进行湖泊健康评价。根据当地湖泊具体情况,选取12个详细指标建立评价体系与评价标准,通过模型计算得出结果显示5个湖泊中4个湖泊评价结果为优,一个评价结果为良,湖泊总体健康状况良好。因此该模型用于湖泊健康评价是非常有效的。