MgO-Cr2O3/Al2O3催化剂对丙烷脱氢反应的再生性能

制备了Mg改性Cr₂O₃/Al₂O₃催化剂,利用XRD,UV-Vis,XPS,H₂-TPR,NH₃-TPD,TG等方法考察了新鲜和再生后催化剂的结构与性能。实验结果表明,助剂Mg的添加有利于催化剂再生后的物相结构稳定;随再生次数的增加,催化剂孔径增大,比表面积降低,催化剂表面Cr⁶⁺含量降低,Cr⁶⁺组分逐渐不可逆还原为Cr³⁺等稳定状态;催化剂表面主要为弱酸和中强酸,随再生次数的增加,酸量减少,但酸强度增加,Cr物种价态及其与载体的相互作用影响了表面酸性进而影响了催化剂活性;新鲜催化剂催化活性略高于再生催化剂,经多次再生后催化剂性能趋于稳定,丙烷转化率稳定在30%左右,丙烯选择性在88%以上。     

新型吸收剂在湿法烟气脱硫中的应用

SO2是现今主要的大气污染物,而我国以煤为主要燃料的特点使SO2的污染日益严重。因此,控制SO2的排放,积极应用二氧化硫控制技术,对改善大气污染状况至关重要。介绍了传统的石灰石一石膏法,探讨了硫酸亚铁法、有机胺法、尿素法、亚硫酸钠循环法、柠檬酸钠循环法、过氧化氢法等应用新型吸收剂的湿法烟气脱硫技术,并对它们的优缺点做了简单评述。     

采用纳米Al203和碳纳米管颗粒强化CO2吸收的理论及实验研究（英文）

The influence of nano-particles on CO2 absorption was studied experimentally in a stirred thermostatic reactor. Nano-A1203 and carbon nanotube （CNT） particles which showed different hydrophobic properties were chosen for the investigation. The experimental results were compared with that of micron-size activated carbon （AC） and Al2O3 particles. From the results, no enhancement by micron-size A1203 was found, and with the increase of A1203 concentration, the enhancement factor decreased. However, nano-Al203 showed a weak enlaancement tor me COz absorption. AC and CNT particles all intensified the gas-liquid mass transfer effectively, yet the trend of the enhancement factor with stirring speed for the two particles was different. With increasing stirring speed, the enhancement factor of AC particles was decreased, wl＇iereas in CNT suspensions it was increased. The experimental phenomena demonstrated a difference in enhancement mechanism for different size particles. For nano-particles, besides the influence of adsorbability and hydrophobicity, the micro-convection caused by Brownian motion should be also taken into account. Considering the micro-convection effect, a theoretical model was developed to shed light on the absorption enhancement bv nano-oarticles.     

分子筛疏水改性对CO2吸收强化的影响

Two methods of the modification of zeolite were employed:framework element modification and surface coating,and the influence of the zeolites before and after modification on the CO₂ absorption was investigated.It was found that although hydrophobicity of zeolite could be obtained by means of the surficial organic coating in the method of surface coating modification,partial channel of zeolite would be plugged,as a result,leading to the surface area reducing greatly.Distinctively,the framework element modification method could maintain not only complete lattice structure and adsorption capability of zeolite,but would also obtain a good hydrophobic property.Consequently,significant enhancement on gas absorption by this modified zeolite was achieved and up to a maxi-mum enhancement factor of 2.62.This shows that the solid particles with good enhancement role to gas absorption need not only good adsorptive capability but also certain hydrophobicity.An unsteady heterogeneous model was employed to predict enhancement factor and the calculated results agree well with the experimental data.     

无溶剂法烷基烯酮二聚体的制备及工艺改进

以三乙胺和硬脂酰氯为原料,采用无溶剂法制备了烷基烯酮二聚体(AKD),为了避免蒸馏法回收过量三乙胺所带来的高能耗,提出了一种新的工艺对AKD后处理过程进行改进,反应产物在热过滤除去三乙胺盐酸盐后,在低温下过滤得到AKD,所得滤液循环使用。研究了不同参数对反应收率和AKD纯度的影响,最佳反应温度为60℃,反应时间为1.5 h。当三乙胺和硬脂酰氯的摩尔比R_(TEA/STC)5时,尽管首次采用新鲜原料时反应收率较低,但并不影响后续的循环反应收率,循环反应收率可达86%,而且较高的原料配比可使反应在较低的黏度下进行。多次的循环实验表明,采用文中所提出的方法,操作易于控制、能耗低、反应条件温和,值得进行工业推广。     

活性炭粒子对K2CO3溶液中CO2化学吸收的强化

The enhancement of chemical absorption of CO2 by K2CO3/H2O absorbents in the presence of activated carbon （AC） particles was investigated. The results show that the gas absorption rates can be enhanced significantly in the presence of AC particles, and the maximum enhancement factor 3.7 was observed at low stirring intensities. The enhancement factor increased rapidly with the solid loading during the initial period of absorption and then be- came mild gradually to a maximum value. Both the liquid-solid contact area and the probability of solid particles residing at the gas-liquid interface decreased with the increase of the particle size, leading to a negative effect on the enhancement of mass transfer. The influence of the particles on gas absorption decreased with the reaction rate. The stirring speed changed the interfacial coverage and mass transfer rate on the liquid side and consequently affected the mass transfer between the gas and liquid phases; the enhancement factor decreased with the stirring intensity. A heterogeneous two-zone model was proposed for predicting the enhancement factor and the calculated results agreed well with the experimental data.     

化工设计课程教学改革模式研究

在化工工程中,化工设计作为可以将化工工程从设想转变为现实的建设,帮助化工工程更好地进行建设和设计。在化工设计的教学中,化工设计涉及了多种不同类型的知识,从化工工艺学、化工设备、化工热力学和物理化学等多种方面进行综合学习。在化工设计课程的教学中,必须要通过对教学模式的改革来帮助教师更好地进行教学,以便提高化工设计课程的教学效率。     

泵与管路设计型实验教学改革初探

本科院校实训基地建设越来越受到重视,探索实训教学内容是工科教师的重要教学任务。根据本科院校现行实验课程、高职院校的实训的情况,进行了泵与管路设计型实验的教学改革尝试。阐明了该实验主要内容和实施的过程,以及实验所取得的成效。通过化工专业的泵与管路的设计型实验实训,培养了学生积极参与的意识,泵与管路的合理选型能力,以及安装调试的技能。     

第三分散相液滴增强气体吸收的一维非稳态非均相传质模型

A model for one-dimensional unsteady heterogeneous mass transfer was developed based on Danckwerts’ surface renewal theory in order to describe the mass transfer enhancement of absorption process for a slightly soluble gas in a gas-liquid-liquid system. The model accounts for the mass transfer resistance within the dispersed phase and the effect of emulsion viscosity on mass transfer. An analytical solution for enhancement factor was obtained by Laplace domain transformation. The absorption rates of carbon dioxide in the dodecane-in-water and castor oil-in-water systems were measured in a thermostatic reactor, and the enhancement factors were calculated at different volume fractions of dispersed phase and stirrer speeds. The model predictions agree well with the experi-mental data.     

塑料用水性油墨新型乳化剂的研究

随着塑料用水性油墨应用范围越来越广,水性油墨的质量尤为重要,而乳化剂的作用最为关键.本文通过实验配制出的新型反应性乳化剂,能明显提高塑料用水性油墨的附着力、干燥速度和耐水性.