过硫酸钠工艺同时氧化吸收燃煤烟气中NO和SO_2的研究

在半间歇式鼓泡床反应器中进行了过硫酸钠工艺同时氧化吸收燃煤烟气中NO和SO2的研究。研究了过硫酸钠浓度、溶液温度、NO初始浓度、SO2初始浓度对体系NO脱除的影响。结果表明,随着Na2S2O8溶液浓度的增加,NO脱除率呈现先增加后变化不大的趋势,0.2 mol/L均为单独脱硝和同时脱硫脱硝的最佳浓度。随着溶液温度的提高、NO初始浓度的降低,NO脱除率显著增加。在所有实验条件下,SO2脱除率均在95%以上。SO2对NO的脱除具有双重作用,一定浓度的SO2,在较低温度范围内,对NO的脱除表现为增强效应,随着温度的升高,增强效应逐渐减弱,在较高温度范围内,转为抑制作用。SO4·-和OH·活性自由基与液相中NO和SO2的相对比例变化是引起NO脱除率变化的根本原因,实验条件的变化直接或间接的改变了这一比例,导致NO脱除率发生变化。     

臭氧/氧化镁同时脱硫脱硝的反应特性

本实验利用一套自行设计的鼓泡反应装置进行了臭氧前置氧化、氧化镁溶液吸收的脱硫脱硝反应特性研究,探索了臭氧浓度、混合烟气温度、吸收液pH值、反应温度、SO_2及NO初始浓度等参数对脱硫脱硝效率的影响。结果显示,高O_3浓度和烟气温度有助于SO_2和NO的脱除,但吸收液pH值和反应温度不宜过高,烟气中的SO_2浓度变化对NO的脱除效率影响甚微。最佳实验条件下SO_2脱除效率可达99%,NO脱除效率可达52%。     

自由基簇射电催化氧化同时脱硫脱硝过程反应特性及机理研究

应用一种新型的电催化氧化技术??电晕放电自由基簇射技术进行了烟气同时脱硫脱硝实验,重点分析了SO2和NOx脱除的反应特性和相互影响机理.结果表明:在0.042 L(min(1的氨气注入下,50%的SO2在放电前被脱除,但放电过程仍对SO2的脱除有一定的促进作用.而NOx的脱除取决于放电过程,放电前的脱除几乎可以忽略不计.在脱除过程中,适量的SO2能够提高NOx的脱除,最大能使NOx脱除率提高25%,但过高的SO2又使NOx的脱除趋于减少.不同SO2初始浓度下NOx脱除率的变化主要归因于SO2和NO2之间的反应.NO初始浓度的变化对SO2的脱除影响较小.烟气成分的变化对SO2和NOx的脱除影响也不明显.在脱硫脱硝过程中,观察到的白色晶体状物质主要成分是硫酸铵和硝酸铵.     

臭氧氧化—钙法吸收同时脱硫脱硝的试验研究

针对国内某石化企业CFB锅炉烟气特点,进行实验室烟气模拟,采用臭氧氧化—钙法吸收同时脱硫脱硝工艺进行小试研究.实验采用臭氧将NO氧化为NO2,再通入鼓泡反应器中与Ca（OH）2浆液发生吸收反应,达到同时脱硫脱硝的目的.实验结果表明：NOx脱除率与臭氧投加量成正比,当臭氧投加量为1.1时,NOx脱除率可达到90％以上;SO2初始浓度的变化对NOx脱除率影响不大;NO初始浓度和烟气含氧量对SO2脱除率影响效果均不显著;烟气含氧量的增大有利于NOx的脱除.     

臭氧氧化结合硫代硫酸钠溶液喷淋同时脱硫脱硝

采用臭氧氧化结合湿法喷淋硫代硫酸钠溶液的方法开展模拟烟气同时脱硫脱硝实验研究。结果表明,采用臭氧氧化结合Na2S2O3-Na OH溶液湿法喷淋可以实现NOx和SO_2协同脱除:在O_3/NO摩尔比为1.1~1.2时,溶液中Na2S2O3浓度的增加会提高系统的NO_x脱除效率,烟气中SO2的存在会促进NOx的脱除,当SO2浓度为1030mg·m~(-3)、2.0%Na_2S_2O_3溶液作为喷淋液时可实现较高的SO_2脱除效率,同时NO_x脱除效率可达70%以上;喷淋液p H在2.5~9范围内变化时提高浆液p H有利于NOx的脱除,当p H=9时脱硝效率可达75%。180 min连续同时脱硫脱硝实验结果表明,硫代硫酸钠可有效促进NOx的脱除,并实现SO2较高的脱除效率,同时可实现系统同时脱硫脱硝连续稳定运行,喷淋吸收后烟气中NO_x的主要转化产物为NO~-_2,该方法作为一种有效的同时脱硫脱硝技术,具有一定的工业应用推广前景。     

UV辐照强化NaClO_2溶液脱硝实验研究

NaClO_2具有非常强的氧化性,在湿法脱硝方面具有良好的应用前景,但该方法存在氧化剂成本较高、利用率偏低等不足。针对该问题,文中采用UV对NaClO_2溶液进行辐照预处理,分别研究了NaClO_2浓度、UV辐照预处理时间、溶液初始pH值对NO脱除效果的影响。结果表明:UV辐照可以明显增强NaClO_2溶液的NO脱除率。当UV辐照预处理时间为1 min时,NaClO_2浓度越低,NO脱除强化效果越明显。当NaClO_2浓度为2 mmol/L时,随UV辐照预处理时间的增加,NO脱除率不断提高,且与无UV辐照预处理时相比,NO脱除强化率最高可达87.5%。当UV辐照预处理时间大于5 min时,NO脱除率可达94%以上。UV辐照预处理前溶液pH值对NO脱除率也会有影响,当NaClO_2溶液初始pH值在5—9范围内时,NO脱除率在60%左右,而当pH值降为3时,NO脱除率可迅速提高至75.3%。利用分光光度法测定了NaClO_2光解后主要产物ClO_2的质量浓度。     

超声雾化过硫酸钠联合氢氧化钙吸收脱硫脱硝

使用超声雾化/紫外光/热量协同活化过硫酸钠(Na_2S_2O_8)溶液,联合Ca(OH)_2吸收作用,脱除烟气中的SO_2和NO,获得了较高的脱除效率。实验研究了影响烟气中SO_2和NO脱除的主要因素,并且对实验过程中的主要活性物质以及反应机理进行了分析。使用超声波雾化器产生的液滴d_(50)值为7.2μm,粒径小于10μm液滴占总数的72%。超声雾化可以加速Na_2S_2O_8溶液在受紫外光/热量协同活化时分解产生SO_4~-·和·OH等自由基,提高污染物的脱除效率。Na_2S_2O_8浓度、UV功率的升高会促进烟气中NO和SO_2的脱除;烟气流量、溶液pH值等参数的升高不利于NO和SO_2的脱除;烟气温度变化对NO的脱除具有双重影响。在最佳的条件下,NO和SO_2的脱除效率分别为97.5%,86.3%。同时确定了该实验体系下脱硫脱硝过程中的主要活性物质为SO_4~-·和·OH。     

用KMnO4调质钙基吸收剂从燃煤烟气同时脱硫脱硝

在固定床反应器中考察了强氧化剂KMnO₄作为添加剂对钙基吸收剂同时脱硫脱硝的调质效果。实验结果表明,不含KMnO₄时钙基吸收剂不能有效脱除NO,而当KMnO₄存在Ca/(S+0.5N)为1.8时,钙基吸收剂可获得31.4％的脱硫率和13.5％的脱硝率。实验还研究了各种参数变化对脱硫率和脱硝率的影响,反应温度升高能够促进SO2的脱除,但脱硝率对温度的变化不敏感;脱硫率随着烟气相对湿度的增加而增加,但脱硝率与相对湿度的关系不是单调的,存在一个最大值;O₂是脱除NO的必要条件。结合气体分析和产物分析的实验结果发现,NO被脱除的机理是先被氧化为NO₂,然后再与吸收剂和脱硫产物反应生成了硝酸盐和亚硝酸盐。为半干法脱硫技术中加入脱硝功能的可能性提供参考依据。     

基于凹凸棒土催化双氧水分解的低温燃煤烟气脱硝

采用凹凸棒土为催化剂,在自主设计的固定床实验台上进行模拟燃煤烟气脱硝实验研究。考察了H_2O_2浓度、H_2O_2汽化温度、催化反应温度以及催化反应时间对催化脱硝性能的影响,分析了催化氧化反应后的液相成分。通过X射线荧光光谱(XRF)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、BET比表面积测定等分析方法对不同反应时间凹凸棒土催化剂的理化结构特性进行表征。脱硝实验结果表明,在H_2O_2溶液浓度为4mol/L、流量为5mL/h条件下,NO脱除效率达到70%,NO脱除效率随着催化反应温度的升高先升高后降低,随H_2O_2浓度和H_2O_2汽化温度的增加而升高。离子色谱(IC)分析结果说明,NO被氧化后得到的液相成分主要为硝酸。结合上述实验结果可知,·OH氧化NO是脱除烟气中NO的主要作用机制。表征结果表明:不同反应时间下凹凸棒土催化剂的结构、成分、孔结构参数等基本保持不变。在4h反应时间内,NO脱除效率基本保持不变,这与催化剂表征结果相一致,说明凹凸棒土作为催化剂具有良好稳定性。     

活性炭混合钢渣烧结烟气脱硫脱硝实验研究

采用混合法用钢渣与活性炭制备混合钢渣活性炭吸附剂，对其进行XRF, BET, SEM和FT-IR等表征，于可编程电加热固定床反应器中进行模拟烧结烟气脱硫脱硝实验，考察反应温度、SO2浓度及[NH3]/[NO]浓度比、O2含量等因素对混合钢渣活性炭的吸附及催化性能的影响。结果表明，模拟烧结烟气中SO2初始浓度0.06vol%, NO初始浓度0.04vol%, O2含量15vol%及反应温度120℃条件下，最高脱硫脱硝率分别为79%和34%。按浓度比[NH3]/[NO]=1通入还原剂NH3时，脱硫脱硝率均升高，表明钢渣具有一定催化还原作用。脱硝率随反应温度升高而下降，O2含量提高有利于混合钢渣活性炭对SO2和NO的吸附。掺混钢渣降低了吸附剂的比表面积，但钢渣中含一定量Fe2O3，具有一定催化还原作用，有利于NO吸附。同时，加入钢渣也是对固废资源的合理利用，达到“以废制污”的目的。     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.