水洗筛板塔设计中的讨论

结合工作实践,阐述对大流量的水洗筛板塔液采用双溢流,无溢流堰的结构可以避免液泛,稳定操作,此类塔采用筛板塔比填料更经济,对大液量筛板塔设计有一定的参考价值。     

泡沫筛板塔在回收粗氯乙烯气体中过量氯化氢成酸的应用总结

本文论述了泡沫筛板塔取代填料塔进行氯化氢气体吸收成酸取得了显著的经济效益和环境效益。     

新型垂直筛板塔在小氮肥生产中的应用

本文通过对小氮肥行业塔设备现状的分析，阐述了新型垂直筛板塔的特点，通过在碳化回收清洗塔，饱和热水塔的改造，表明新型垂直筛板塔具有优越的综合性能。     

新型垂直筛板塔在变换气脱硫系统中的应用

介绍了变换气脱硫塔的塔型选择，从传统的填料塔到现在的垂直筛板塔的观念改变，垂直筛板塔的优势、设计和安装中的注意事项。     

分散降液筛板塔传质性能

在筛板塔的基础上,研发了一种新型板式塔--分散降液筛板塔,将传统筛板塔的弓形降液管改为均布于塔板筛孔间的多降液管结构,使整个塔板面成为均匀降液和受液的传质区,并新增淋降和喷溅传质区,在全塔空间内实现立体、连续的微分接触式气液传质过程,另外,塔板之间可以加装填料来强化传质,或装填催化剂以促进伴随化学反应的传质过程。以“氧气-空气-水”为体系,初步研究了分散降液筛板的传质性能及其影响因素,并与传统筛板进行比较,结果表明:分散降液筛板气液分布均匀,接触充分,在同等条件下传质效率比传统筛板提高了8.4%~9.7%。     

溢流筛板塔汽提技术在PVC生产中的应用

介绍了溢流筛板塔的结构及溢流筛板塔汽提技术的工艺流程、工艺指标和技术特点,并与穿流筛板塔进行了技术比较。指出溢流筛板塔汽提效率高,脱出VCM的能力强,可使PVC中残留VCM含量在1×10-6以下。     

筛板蒸氨塔的设计

对国内首次开发设计的筛板蒸氨塔的设计特点进行了分析,并详细介绍了该塔的设计要点,对设计工作进行了总结。对筛板蒸氨塔的维修、生产管理具有一定的指导意义。     

不同开孔方式的大孔筛板干板压降研究

评价塔设备性能的主要指标之一就是塔板压强降。干板压降是筛板塔总压降的主导部分。本文以降低筛板的干板压降为目标,使用标准k-ε湍流模型,对不同开孔方式的大孔筛板进行了模拟计算,定量地讨论了筛板开孔方式对筛板干板压降的影响效果。模拟结果表明,下锥形筛板不利于降低干板压降,而具有合适锥度的上锥形筛板与普通筛板相比是可以降低干板压降的。经过光滑处理的弧形上锥形筛板虽然对减少结焦反应有利,但在降低干板压降方面没有明显的作用。     

筛板上从泡沫工况向喷射工况转变气速的计算模型

<正>筛板塔是应用历史最久的塔型之一。至今人们仍在对筛板塔进行大量的研究,但对筛板塔处于不同鼓泡层的结构及筛板塔各操作状态之间的划分这一课题,还基本上限于一些定性的直观描述。筛板塔的各操作状态之间主要由两点速度划分,即漏液气速和喷射转变气速。在他们之间筛板处于泡沫工况,当气速高于喷射转变气速时,筛板塔处于喷射工况。这两种工况是人们最感兴趣的,这不仅因为在工业上这两种工况用得最多,而且还因为在流动泡沫工况下气体为分散相,液体为连续相,一旦转变为喷射工况就发生了相变,气体变为连续相,原来是连续相的液体则被气体吹散为小液滴的分散相。这种工况的转变必然强烈地影响着两相间的传质,要掌握塔板上两相间的传质规律,首先要确定它是处于何种工况。     

丙烯酰胺水溶液浓缩的载气蒸发新方法

提出了一种丙烯酰胺水溶液浓缩的载气蒸发新方法,分析和讨论了该方法的基本原理,介绍了载气蒸发新方法的技术方案.该丙烯酰胺水溶液浓缩载气蒸发法的特点是在一般筛板浓缩塔的筛板上布置了加热管,把一般筛板塔浓缩的平衡控制过程转变为传热控制过程.依据新方法开发的新型载气蒸发筛板塔可采用多层塔板操作,该塔与未设置加热管且塔板较少的情况相比,浓缩比可以提高1倍;采用负压操作,可以避免丙烯酰胺泄漏.     

丙交酯制备过程中几种影响因素的研究

以L-乳酸为原料在催化剂存在的条件下,加热脱水、裂解合成了L-丙交酯。研究了脱水温度、脱水时间、裂化反应温度及催化剂种类对丙交酯产率的影响。通过正交实验确定的最优反应条件为:脱水温度120℃、脱水时间4h、裂化温度240℃、催化剂为辛酸亚锡,并通过工艺的改进,大幅提高了丙交酯的产率,达到56.9%。     

Evaluation of the ratio of the evaporation energy to the activation energy for estimating the thermodiffusion coefficient

Thermodiffusion has an important role in displacements of hydrocarbon reservoir. The ratio of the evaporation energy to the activation energy of viscous flow in pure limits, τ_pure,k, is of a great importance in estimating the thermodiffusion coefficient for non‐associating fluid mixtures. Several methods may be used to estimate τ_pure,k which causes different values for thermodiffusion coefficients. A fixed value for τ_pure,k was considered to predict the thermodiffusion coefficient. In this paper, Abbasi et al.'s [J. Non‐Equilib. Thermodyn. 2010;35:1–14] model and Shukla and Firoozabadi's model have been applied to predict thermodiffusion coefficients for linear chain hydrocarbon binary mixtures. The results show a very good performance of the simple approach in respect to the previous models in estimating thermodiffusion coefficients. © 2011 Canadian Society for Chemical Engineering     

火灾对施工中系杆拱桥混凝土箱梁性能的影响分析

为了研究系杆拱桥火灾后混凝土和箱梁损伤程度的大小和性能的变化,针对火灾后一座1～64 m系杆拱桥的过火结构进行检测和分析,并现场取样对火灾过程中混凝土箱梁温度场、混凝土受损程度、火灾后混凝土微观结构等进行实验分析,得到系杆拱桥在遭受火灾后各项性能的变化,为桥梁火灾检测提供一种可靠的的检测方案和检测依据,得到高温后混凝土性能变化,同时建立该桥的有限元模型,模拟得到的火灾后系杆拱桥承载力及变形等性能的变化情况和实测结果基本一致,为桥梁火灾后受损情况鉴定提供了一种可行的有限元模拟方法.     

试论全日制专业学位研究生思想政治教育的特点、难点和突破点

目前,全日制专业学位研究生在校生已具有相当规模,他们的思想状况究竟有哪些特质,给我们的思政工作带来了哪些新挑战,突破点在哪里？这些都是我们亟待解决的问题。本文旨在结合作者的工作体会,对以上问题进行探究。     

On the effect of the nature of the side chain over the crystalline structure in aliphatic polyketones

The crystalline structure of a number of random polymers of perfectly alternating l-olefins/carbon monoxide aliphatic polyketones has been studied by wide angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and Raman spectroscopy. From previous studies, WAXS, Raman and DSC have shown to be suitable techniques for the characterisation of the two crystalline polymorphs, α (denser) and β, detected in ethene/carbon monoxide (ECO) and in ethene/propene/carbon monoxide (EPCO) polymers. In this paper for the first time, polyketones with butene and hexene as the second olefin are reported. It was found that the ethene/propene/carbon monoxide polymers and ethene/butene/carbon monoxide (EBCO) polymers, predominately contain the β-rich crystalline phase. The crystalline density of this phase drops with increasing second olefin content, albeit at a faster pace for propene polymers. From the latter results, and from the behaviour of the melting point, crystallinity, and crystal thickness across composition, inclusion of methyl and ethyl side chains into the crystals as defects was inferred. Ethene/hexene/carbon monoxide (EHCO) polymers do seem to behave differently: they show lower crystallinity, the presence of a larger quantity of the denser α crystals and a relatively high and constant crystalline density for the β phase throughout composition; observations that unambiguously support the exclusion argument for the butyl branches. The above behaviour is surprising since for instance in polyethylene copolymers it is considered that only methyl branches can enter the crystal lattice. The relative presence of α crystals was found to decrease with increasing the concentration of branches and in the order EHCO>EBCO>EPCO.     

瓷釉涂层/金属基体界面分形维数的研究

研究瓷釉涂层和金属基体界面形貌的分形特征,建立了分形曲线的提取模型,用计盒维数法计算分形维数,并和落球冲击试验结果相比较,发现分形维数的变化和瓷层的密着性的好坏呈现相同的变化趋势.分形理论为研究喷瓷管道的密着性提供了一种新的方法,为深入研究瓷层的密着性奠定了基础.     

铸造用酚醛树脂生产中有关技术问题探讨

针对铸造用酚醛树脂类粘结剂生产中出现的产品中苯酚、甲醛、水分含量高，树脂储存稳定性差、产品出现凝胶物等现象，从工艺、设备、操作等方面分析了生产中存在的问题，提出了一些已被生产实践证明的合理的解决方案。     

空分精馏系统最佳氩馏分位置的确定

指出在同时生产高纯度的氢、氮及粗氩产品，并带粗氩塔的空气分离双级精馏系统中，双级精馏塔的上塔存在最佳抽氩馏分位置，并介绍其确定方法。     

硝酸磷肥的现状与发展之我见

硝酸磷肥的工艺流程有多种。介绍了国内外硝酸磷肥的发展简况 ,我国 90 0kt/a间接冷冻法和 16 5kt/a混酸法两套硝酸磷肥装置的生产方法和特点 ,分析了上述混酸工艺改为磷酸—硝酸混酸工艺后 ,可随时调整产品中有效养分的比例 ,有利于参与国内外市场竞争 ,并对新建硝酸磷肥装置就建厂条件、生产规模、工艺路线和原料供应等提出建议。     

Utilizing the power of microbial genetics to bridge the gap between the promise and the application of marine natural products

Marine organisms are a rich source of secondary metabolites. They have yielded thousands of compounds with a broad range of biomedical applications. Thus far, samples required for preclinical and clinical studies have been obtained by collection from the wild, by mariculture, and by total chemical synthesis. However, for a number of complex marine metabolites, none of these options is feasible for either economic or environmental reasons. In order to proceed with the development of many of these promising therapeutic compounds, a reliable and renewable source must be found. Over the last twenty years, the study of microbial secondary metabolites has greatly advanced our understanding of how nature utilizes simple starting materials to yield complex small molecules. Much of this work has focused on polyketides and nonribosomal peptides, two classes of molecules that are prevalent in marine micro- and macroorganisms. The lessons learned from the study of terrestrial metabolite biosynthesis are now being applied to the marine world. As techniques for cloning and heterologous expression of biosynthetic pathways continue to improve, they may provide our greatest hope for bridging the gap between the promise and application of many marine natural products.