不同比表积的Pt负载型催化剂上甲醛催化氧化

为研究铂负载型催化剂时甲醛催化氧化反应的活性,采用溶胶一凝胶法制备了不同载体的铂负载型催化剂,并对催化剂进行XRD、Raman等表征,考察所制催化剂对甲醛催化氧化反应性能。结果表明：载体的性质在反应中起到重要作用,惰性载体无法促进氧的活化,其催化活性较低;对比不同比表面积的Pt／CeO2催化剂,发现比表面积为38mVg的催化剂的催化氧化性能最佳,这与催化剂的氧缺位浓度较高及较强的金属一载体间相互作用有关。     

甲醛气相光催化降解特性探究

探讨了可见光照射下,甲醛气体的光催化降解行为.结果表明,催化剂用量增加,甲醛气相光催化降解速率增加,当催化剂达到一定量后,甲醛气相光催化降解速率不再增加;甲醛气体初始浓度增加,光催化反应速率亦增加,但过高的初始浓度会使光催化反应速率或甲醛降解率降低;甲醛气相光催化反应过程中氧气O2和水H2O对于反应的进行都是必不可少的,但过多的水分却对光催化反应有抑制作用;甲醛气相光催化反应符合Langmuir-Hinshelwood(L-H)动力学模型.     

醋酸/甲醛缩合合成丙烯酸研究

采用溶胶-凝胶法制备了钒-钛-磷系醋酸/甲醛合成丙烯酸的催化剂,通过XRD和电镜表征催化剂结构,并考察了催化剂的焙烧温度、钒钛比、活性评价温度及酸/醛比对催化剂的影响。研究结果表明,V-TiP三元氧化物/SiO2/氧化铝为无定形态,且分布较均匀,该催化剂合适的钒钛比约为1:1,适宜的焙烧温度为500℃;反应过程中适宜的反应温度为350℃,适宜的酸/醛比为3:1。     

甲烷催化氧化成甲醛

介绍甲烷氧化成甲醛及其催化剂和反应历程。     

甲醇氧化成甲醛的生产条件研究

在精细有机化工生产中,氧化是一类重要的化学反应过程.通过氧化反应可以制取醇、醛、酮、酸、酸酐等多种产品,其中,催化剂的应用是工艺的灵魂,它常常在很大程度上决定着生产的水平及其创新程度.按氧化剂的不同,氧化反应可分为空气氧化和化学氧化.本文分析了甲醇氧化成甲醛的反应动力学,以及催化剂的研究、选择、组成和制备,探讨了生产甲醛的操作条件、反应设备、产品质量及工艺过程的一般规律.     

含钼、磷催化剂对二苯并噻吩的氧化脱硫研究

以二苯并噻吩（DBT）的甲苯液作为含硫模拟油品,采用以SiO2为负载的含Mo,P的催化剂,以油溶性的过氧化氢异丙苯（CHP）为氧化剂进行氧化脱硫的研究。考察了反应温度、氧化剂用量、反应时间和催化剂用量等因素对DBT脱除率的影响。结果表明,催化剂具有较高的氧化脱硫活性,DBT的脱除率达96%以上。通过正交试验确定了最佳反应温度为90℃,氧硫比为2.5：1,反应时间为2.5h,催化剂用量为0.25g。     

含钒SnO_2催化剂使醇氧化制醛实验的初探

含钒-SnO_2催化剂不仅对甲醇选择性氧化制甲醛适用,而对乙醇选择性氧化制乙醛的效果也很好。 一、实验部分 1.Sn_(1-x)V_xO_2催化剂的制备 将分析纯SnO_2研碎,经200目/时筛得其SnO_2粉末,然后按下列配比与分析纯V_2O_5粉末混合:     

Keggin型钼钒磷杂多酸催化H_2O_2氧化蒽制备蒽醌

实验制备了三种Keggin型钼钒磷杂多酸催化剂,并将其应用于催化H2O2氧化蒽制备蒽醌,考察了各种因素对蒽醌产率的影响,以H5PMo10V2O40为催化剂,催化H2O2氧化蒽制蒽醌的最佳条件为:正丁醇为溶剂,催化剂用量为反应物的6%,蒽:H2O2物质的量比为1:16,反应温度70℃,反应时间2h,产率可达90%以上.     

负载型CeO_2催化剂上CO_2氧化乙烷制乙烯反应研究

采用浸渍法制备负载型CeO2催化剂,应用XRD、SEM技术对所制催化剂进行物相和形貌分析.在常压连续流动固定床石英反应器上考察其在CO2氧化乙烷制乙烯反应的催化性能,实验结果表明:CeO2/-γA l2O3催化剂对CO2氧化乙烷制乙烯反应具有较好的催化活性.当CeO2负载量为15%时,乙烷的转化率为25.8%,乙烯的选择性和收率分别为95.8%和24.7%.     

Mn-Fe/γ-Al_2O_3的制备与NO催化氧化性能

以锰铁为活性中心,γ-Al2O3为载体,采用等体积浸渍法合成了Mn-Fe/γ-Al2O3催化剂,考察了负载量、锰铁比及碱中和等对NO催化氧化活性的影响。结果发现,当反应温度为300℃、入口NO浓度为300 mmol/L、O2浓度为5%及空速为12 000 h-1时,以负载量为20%,Mn/Fe=1及(CH3)4NOH进行碱中和所制得的催化剂转化率最高,为66%,而其他制备条件所获得的催化剂都低于此值。通过对催化剂进行XRD、SEM表征,考察了负载量及碱中和对催化剂物相结构及表面形貌的影响。结果表明,随着负载量的增加,样品晶相不断分离,Fe2O3及MnO2的衍射峰逐渐尖锐,即活性组分进入载体孔道内部。另外,浸渍过程的碱中和操作有利于提高颗粒表面的分散度及形成无定形态。     

Decomposition of dimethyl sulfide in a wire-cylinder pulse corona reactor

Decomposition of dimethyl sulfide （DMS） in air was investigated experimentally by using a wire-cylinder dielectric barrier discharge （DBD） reactor at room temperature and atmospheric pressure. A new type of high pulse voltage source with a thyratron switch and a Blumlein pulse-forming network （BPFN） was adopted in our experiments. The maximum power output of the pulse voltage source and the maximum peak voltage were 1 kW and 100 kV, respectively. The important parameters affecting odor decomposition, including peak voltage, pulse frequency, gas flow rate, initial concentration, and humidity, which influenced the removal efficiency, were investigated. The results showed that DMS could be treated effectively and almost a 100% removal efficiency was achieved at the conditions with an initial concentration of 832 mg/m3 and a gas flow rate of 1000 ml/min. Humidity boosts the removal efficiency and improves the energy yield （EY） greatly. The EY of 832 mg/m3 DMS was 2.87 mg/kJ when the relative humidity was above 30%. In the case of DMS removal, the ozone and nitrogen oxides were observed in the exhaust gas. The carbon and sulfur elements of DMS were mainly converted to carbon dioxide, carbon monoxide and sulfur dioxide. Moreover, sulfur was discovered in the reactor. According to the results, the optimization design for the reactor and the matching of high pulse voltage source can be reckoned.     

Tiny pollutant emissions of a dimethyl ether fuelled engine

Emissions of dimethyl ether （DME） fuelled engines were investigated by orthogonal experiments on a ZS195 diesel engine. The study mainly focused on the tiny pollutant emissions of formaldehyde （CH2O）, methyl formate （CH3OCHO） and formic acid （HCOOH）. The presence of CH2O, CH3OCHO and HCOOH are proved in the exhaust by gas chromatograph and Fourier transform infrared spectroscopy. The analysis of variance results indicate that the fuel delivery advance angle is the most important factor for CH2O emission. The fuel delivery advance angle and the interaction of injection pressure and nozzle diameter are considerable factors for unburned hydrocarbon （UHC） emission. The mechanism forming tiny pollutants, primarily through CH2O formation, is suggested to be similar to the mechanism forming UHC by DME partial oxidation existing in crevices and boundary zones, and is verified via DME combustion simulation of a multizone chemical kinetic model.     

One-dimensional coupled model for landfill gas and water transport in layered unsaturated soil cover systems

Cover systems are used to prevent water infiltration into a waste body. They also play an important role in controlling landfill gas transport from the waste body to the atmosphere. It is important to assess the flux of landfill gas at the surface of a cover system by considering the coupled effects of rainwater infiltration and gas transport in the cover soils. We have developed a 1D mathematical model for coupled transient gas and water transport in unsaturated cover soils. The coupled model was solved by the finite element method. Results obtained by the proposed model agreed well with experimental data. Based on the proposed solution, the influences of gas pressure, gas permeability, and the thickness of the cover soils on soil gas concentration profiles were investigated. The difference in soil gas concentration reached up to 31% as the thickness of cover increased from 1 to 2 m. Gas concentration at a depth of 0.2 m decreased by 6% as the amplitude of atmospheric gas pressure fluctuation increased from 20 to 100 Pa. The gas concentration increased by only 3% when gas permeability increased by a factor of 2 for a relatively long period of gas migration (e.g., 60 h) under the given conditions. Results suggest that both diffusion and advection should be considered when estimating gas transport in unsaturated cover soils. The numerical model can be used in the design of cover systems in relation to gas breakthrough time, breakthrough concentration, and flux.     

定压稳态气测渗透率仪的研制

为保证测定结果的唯一性和稳定性,借鉴了储气筒活塞均匀移动稳压的原理,采用高精度玻璃筒代替传统的外接高压气瓶供气,气筒中密封可移动活塞,活塞在储气筒中匀速移动时受力平衡,储气筒中气体压力不变,通过对储气筒活塞加重块重量的设定,可以改变测量压差。在测定岩石渗透率的过程中,出口端压力为大气压,气体以稳定的状态通过岩心,得到相对稳定的渗透率值。虽然测定中采用的进口压力不同,结果有很大差异,然而当岩心在同一压差下测量时,测得的渗透率的误差可以保持在1％范围内,对不同的岩心在同一压差下测得的渗透率值大小也有了可对比性。     

改性牡蛎壳去除Fe3＋离子废水的研究

提出用改型牡蛎壳去除Fe3＋离子废水的新方法．在常压静态吸附实验中Fe3璃子浓度为1mg/L温度为30℃,pH值为3,实验结果表明：处理时间为1h时去除效率最高．在动态吸附实验条件下得出Fe3＋单位质量滤料的工作吸附量为0．1736mg．利用改性牡蛎壳材料处理含Fe3＋离子废水,具有去除效果较好,操作简单等优点,以废治废,具有双重利用价值．     

循环流化床烟气脱硫实验研究(英文)

本文在一变速循环流化床反应器试验台上进行了烟气脱硫实验．当Ｃａ／Ｓ摩尔比为１．１,并用两相流喷嘴向反应器内喷入适量水时,脱硫效率可以达到８０％以上．     

纳米锰钛催化剂制备及其光催化降解甲醛的研究

选取镍镉网为基体,利用硫酸氧钛和醋酸锰合成了一种锰钛光催化剂,XRD分析其主要由锐钛矿型的TiO2晶体及α-MnO2构成,根据Scherrer方程计算晶粒尺寸约为20nm和30nm。以甲醛为污染物,研究了污染物初始浓度、催化剂用量、反应相对湿度和光能量等反应条件对甲醛降解效率的影响,通过实验得出了最佳的反应条件。     

分级型指数模式在室内空气质量评价中的应用

提出了室内空气质量的评价标准,建立了室内空气质量的评价等级,选取二氧化碳(CO2)、可吸入颗粒物(PM10)、甲醛(HCHO)三种污染物作为评价因子,应用分级型指数模式计算室内空气质量指数,实例说明该评价模式是一种客观有效的方法.     

液态甲醛诱导小鼠肝损伤及纤维化研究

建立液态甲醛诱导小鼠肝损伤及其纤维化模型,并初步观察小鼠肝组织的病变过程．将正常昆明小鼠随机分为实验组和对照组．实验组小鼠注射15％的甲醛溶液,注射量为1mL／kg,每周注射两次,并且每天用1％的甲醛溶液喂养．对照组小鼠以纯净水正常喂养,分别在实验开始后的第3、6、8周处死实验组小鼠各4只,肉眼及病理切片观察其肝脏形态的改变,发现小鼠的体重均呈增长趋势．与实验组小鼠比较,对照组小鼠体重增长显著（P〈0．05）．第8周小鼠肝脏出现明显的病变,表面粗糙,颜色暗黄,出现深色斑点．在石蜡切片中可观察到肝脏组织变得松散,窦周隙（Disse’s space）增大．肝星状细胞（hepatic stellate cell,HSC）较对照组明显增多．随着甲醛处理时间的延长,HSC不同程度地增多,肝损伤病变程度越来越严重．