玻璃纤维湿纱含水快速检测方法及应用

玻璃纤维的生产工艺决定了在其生产过程中含有8%~13%的水,在后道工序中必须去除(即烘干),而湿纱含水量的多少将直接影响玻璃纤维的品质,因此在生产过程中必须严格控制湿纱含水量,如何快速、准确地检测出生产过程中的湿纱含水量将提高对产品质量的控制,减少不合格品的数量。本文通过对现有品种湿纱含水检测的不同方法比较,得出快速检测方法具备先进性;又通过试验说明了快速检测方法的在实际应用中存在的问题及其解决方法。     

丝网波纹填料塔液泛水力学特征

在炼油、石油化工、精细化厂、食品及医药等部门,塔器均属量大面广的重要单元设备,其投资-般占投资总额的20%左右,有些甚至高达50%,塔器广泛应用于蒸馏、吸收、萃取、洗涤、传热等单元操作中。因此塔器的研究一直受到国内外学者普遍关注。由于规整填料塔具有效率高、压降低、放大效应不明显等优点,使其应用越来越广泛^[1-2]。同时填料塔也是过程工业中能量消耗最大的单元操作之一。在设计填料塔时,一般按液泛气速的60%~70%确定载点气速,按液泛气速的50%~60%确定操作气速。尤其在工业实际应用中,大部分操作都是依据长期积累的操作经验使填料塔工作在所谓的"最优化"操作状态,因此填料塔的操作状态都比较保守,目的都是为了避免塔器在长周期运行过程中发生液泛而停产,给企业带来经济损失。液泛现象一直以来都是制约填料塔设计和提高填料塔能量利用率的瓶颈问题,所以关于预测控制填料塔液泛性能的研究是填料塔优化节能研究的关键^[3-4]。只要能对填料塔的操作状态进行实时监控,根据填料塔工作监控的特征参数,可以实时和及时地调整填料塔的操作性能,从而避免填料塔发生液泛,同时根据工艺和生产的需要实时改变填料塔的操作性能,使得填料塔工作在最优化的状态,也符合节能减排的目的。有关填料塔液泛水力学方面的研究已经有很长一段时间。早期的很多研究者都是从散堆填料的研究推广到规整填料的研究,Sherwood等^[5-6]在测定填料塔水力学压降实验的基础上,讨论了填料塔的载液和液泛现象,并提出了压降通用关联图(GDPC)。Eckert等^[7-9]得到了不同填料类型填料塔水力学压降液泛曲线图。Kuzniewska-Lach^[10]以量纲1方法对填料塔流体物性和填料几何参数进行了分析,提出了基于填料类型的泛点预测。Ondracek等^[11]通过填料塔气体或液体入口速度周期性波动操作,进行了液泛滞后效应的实验研究,对工业塔操作更接近液泛点有一定的指导作用。根据上面的这些研究,分析预测填料塔液泛特征的规律,需要从不同方面进行深入的研究。本文以空气和水为实验介质,研究了规整填料塔在各个操作阶段的水力学特征及区别,得到了填料塔液泛水力学压降离散特征分布规律和压降频率分布规律,为预测控制填料塔液泛现象提供了指导。     

Cotton gauze-hydrogel composites: Valuable tools for electrically modulated drug delivery

Cotton gauze was inserted into a hydrogel network composed of acrylamide, sodium methacrylate, and polyethylene glycol dimethacrylate to fabricate an electroresponsive delivery system for wound dressing. The composite was characterized by swelling measurements, showing that shrinking or swelling depend on the applied voltage. The release profile of incorporated diclofenac sodium salt shows the possibility to modulate the kinetics by changes in the amplitude and duration of applied electric pulses. Mathematical models allow a characterization of release profiles, which are slower when an external voltage of 6, 12, and 18 V is applied, and faster at 24 V.     

纱布折叠包装一体输送连线机的设计

目的为了提高纱布的生产效率和增加运行系统的稳定性。方法提出一种折叠包装一体输送连线机,通过2根输送带夹持着纱布片运送到包装机输送带表面,并在置料板和压料板对纱布片进行翻转和挤压处理后,将其平稳放置于包装机输送带,且在夹取纱布片时采用分料轮与下输送带主动轮的间隙配合来实现。结果加工测试结果表明,实现了纱布片折叠机和包装机自动连线化生产,在纱布的实际加工生产中有着较高的实用价值,同时也为生产设备达到最佳使用效果打好基础,进一步提高了产品质量。结论节省了人工成本,提高了工作效率,避免了生产过程中纱布片被污染,为加工出满足各项指标的产品提供一流的设备,更大程度地提高产品质量。     

350 MW GE机组汽轮机电液控制系统阀门突关问题的技术分析

分析了GE机组汽轮机电液控制系统阀门突关的原因。指出阀门突关的直接原因是EH油油质差导致伺服阀人口滤网堵塞所致,而污染EH油的微粒是油动机油缸及EH油泵活塞磨损所产生的金属屑。针对提高EH油油质,提出了防范措施和改进建议。     

彩色医用纱布的加工

介绍彩色医用纱布的加工过程,筛选特殊染料进行染色以满足药典对医用纱布的要求;针对纱布组织稀疏的特点,优选合理的工艺与设备配置.     

水刺非织造布替代脱脂纱布的可行性研究

对水刺法非织造布与传统脱脂纱布的医用性能和技术指标进行了比较和对照分析,重点介绍了医用水刺非织造布的特点及其使用性能,并讨论了用其替代传统脱脂纱布的可行性。     

Rational modeling of the CPO of methane over platinum gauze: Elementary gas-phase and surface mechanisms coupled with flow simulations

The high-temperature catalytic partial oxidation of methane (CPOM) over a platinum gauze reactor was modeled by integrating 3D numerical simulations of the flow field coupled with heat transport as well as detailed micro-kinetic models including gas-phase and surface reaction mechanisms. Model results describe well CPO experiments over Pt-gauzes in the literature. The conversions of CH₄ and O₂ increase with an increased contact time and were constant in the temperature range of 1000–1200 K. The selectivity to CO linearly increases with temperature. H₂ was only observed above 1200 K, below this temperature H₂O was the only hydrogen-containing product. The contribution of heterogeneous steps in the overall process is prominent, but in the later stages of the reactor, gas-phase reactions become important at certain conditions of temperature, pressure and residence time. Simulations predicted significant gas-phase production of ethane and ethylene via methane oxidative coupling upon increasing the total pressure and residence time. Consequently, homogeneous and heterogeneous processes should be simultaneously implemented in order to accomplish a solid reactor modeling.     

Mechanistic insights into the formation of N2O and N2 in NO reduction by NH3 over a polycrystalline platinum catalyst

The reaction pathways of N₂ and N₂O formation in the direct decomposition and reduction of NO by NH₃ were investigated over a polycrystalline Pt catalyst between 323 and 973 K by transient experiments using the temporal analysis of products (TAP-2) reactor. The interaction between nitric oxide and ammonia was studied in the sequential pulse mode applying ¹⁵NO. Differently labelled nitrogen and nitrous oxide molecules were detected. In both, direct NO decomposition and NH₃–NO interaction, N₂O formation was most marked between 573 and 673 K, whereas N₂ formation dominated at higher temperatures. An unusual interruption of nitrogen formation in the ¹⁵NO pulse at 473 K was caused by an inhibiting effect of adsorbed NO species. The detailed analysis of the product distribution at this temperature clearly indicates different reaction pathways leading to the product formation. Nitrogen formation occurs via recombination of nitrogen atoms formed by dissociation of nitric oxide or/and complete dehydrogenation of ammonia. N₂O is formed via recombination of adsorbed NO molecules. Additionally, both products are formed via interactions between adsorbed ammonia fragments and nitric oxide.     

硝酸工业用钯合金捕集网的应用研究进展

概述了硝酸工业用铂合金催化网中铂的损耗形式，高温条件下铂的损耗机理，铂的回收方法，钯合金捕集网法回收铂的原理以及钯合金捕集网的发展和研究现状，展望了钯合金捕集网在硝酸工业中的应用前景。