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北京化工研究院乙烯制二氯乙烷新型催化剂通过验收　　 2 0 0 1年 1月 5日 ,北京化工研究院承担的“九五”国家重点攻关项目———“第二代氧气法乙烯氧氯化制二氯乙烷催化剂开发及工业应用研究”通过国家石化局科技办组织的总结验收。该项目解决了催化剂制备中多组分共沉淀的技术难题 ,采用共沉淀法制备的新一代氧气法乙烯氧氯化制二氯乙烷催化剂在模拟工业生产条件下 ,在实验室流化床中进行了氧氯化反应评价 ,ＨＣｌ转化率大于 99.5 % ,二氯乙烷纯度大于 99% ,尾气中ＣＯ2 小于 1% ,性能优于目前使用的进口催化剂。现已建成 5 0ｔ/ａ催化…     

氯化氢催化氧化制氯气工艺

对于氯化氢催化氧化制氯气过程， Cu含量约为12%、主要组份为CuO的负载型催化剂活性高，连续使用200 h活性保持不变. 将工艺的流程分为氧氯化段和氯化段，既无需对反应过程供热，又能使HCl完全转化成氯气. 氧氯化过程的适宜反应条件为：温度360~400℃，原料气的进料比HCl:O2=2:1，进料总质量空速0.3~0.4 kg/(kg催化剂.h)(以下均简称h–1); 氯化段温度为200℃左右.     

氯化反应过程中氯资源的循环利用

以甲苯氯化副产物HCl作为氧化反应原料,采用γ-Al2O3负载铬活性组分的催化剂,在固定床反应器中进行氯化氢氧化制氯气工艺试验。在氧化反应温度为360℃、HCl/O2物质的量比为1∶1时,氯化氢转化率可达到85%以上。将氧化反应得到的混和气体循环使用于甲苯氯化反应,氯气利用率可达100%,实现了有机氯化反应中氯原子的循环利用。     

乙烯氧氯化制二氯乙烷催化剂的研制

研制出一种负载Cu及K的乙烯氧氯化制二氯乙烷的催化剂,考察了反应条件对催化活性的影响,并与进口催化剂以不同比例混合构成掺混催化剂,在加压流化床反应器中进行活性评价。结果表明:氯化氢转化率大于99.9%,二氯乙烷选择性大于99.7%,均达到了进口催化剂的水平。     

邻、对氯苯甲酸的无溶剂合成

无溶剂条件下,利用分子氧液相催化氧化邻、对氯甲苯同分异构混合物合成氯苯甲酸。考察了催化剂配比及用量、反应温度、氧气流量等因素对氯苯甲酸收率的影响,确定的适宜氧化工艺参数为:环烷酸钴用量0.5%,四溴乙烷用量0.107%,反应温度150℃,氧气流量9.65mL/s,反应时间10h后,氯苯甲酸总收率可以达到30.54%。     

两段循环流化床中氯化氢催化氧化制氯气

在两段循环流化床反应器中进行氯化氢催化氧化制氯气的实验. 研究表明,HCl转化率比普通流化床有大幅度提高. 当主要组分为CuCl2的负载型催化剂中的Cu含量为5%时,能够保证反应器的连续顺利运转,而且具有较高的催化活性. 氧氯化段的适宜反应温度为390~400℃,氯化段适宜的反应温度为200~240℃. 在较低的HCl进料空速或较高的O2与HCl进料体积比条件下,HCl转化率较高.     

流化床乙烯氧氯化制二氯乙烷催化剂研究进展

聚氯乙烯(PVC)是由氯乙烯单体聚合而成,乙烯氧氯化制氯乙烯工艺是目前世界上广为采用的氯乙烯单体制备方法。乙烯氧氯化制二氯乙烷是乙烯法生产聚氯乙烯的关键步骤,其核心是乙烯氧氯化制二氯乙烷催化剂。介绍了近年来用于流化床乙烯氧氯化反应的催化剂的开发应用现状和发展趋势。     

以生物甘油为原料制备环氧氯丙烷的研究

以生物甘油为原料,经氯化反应和环化反应制备了环氧氯丙烷。首先以生物甘油为原料、以氯化氢气体为氯化剂、以己二酸为催化剂,采用无水Na2SO4除水4次,制得二氯丙醇（DCP）,氯化收率达90.09%;再以二氯丙醇和氢氧化钠反应制得环氧氯丙烷,通过单因素实验,得到环化反应的最佳工艺条件为：反应时间30min、氢氧化钠与二氯丙醇摩尔比1.15∶1、反应温度95℃,在此条件下的环化收率为88.2%。     

第二代氧气法乙烯氧氯化制二氯乙烷催化剂

采用共沉淀法,加入第二组分和第三组分作为助催化剂制备的Cu/Al2O3催化剂,用于流化床氧气法乙烯氧氯化制二氯乙烷反应,可以有效地抑制乙烯深度氧化生成二氧化碳反应,提高二氯乙烷的纯度。在国内现有的两套20万t/a的氯乙烯生产装置上推广使用该催化剂,将收到可观的经济效益。同时,使用此催化剂生成的二氧化碳和其它氯化物较少,有利于环境保护。     

乙烯氧氯化反应动力学测定

介绍了采用浅床层固定床反应器,在近似工业条件下对AKZO公司开发的FPC-2LD催化剂进行了氧气法乙烯氧氯化制二氯乙烷的本征动力学研究,用多元线性回归数学模型对实验数据进行计算,建立了该催化剂的主反应动力学方程式。     

Experimental and numerical study of applicability of porous combustors for HCl synthesis

Porous combustors have been studied intensively concerning the combustion of natural gas. The advantages of combustion in porous inert media, such as low emissions, high power turndown ratio of typically 10:1 and compactness, can also be used for different chemical gas phase reactions, e.g. the HCl synthesis from H₂ and Cl₂. The advantages of porous reactors result from the heat transport properties of the porous medium, i.e. emissivity and conductivity. Heat transport mechanisms and chemical reactions were implemented in a numerical code in order to investigate the H₂/Cl₂ system. Important parameters of the reaction, e.g. the laminar flame speed and the adiabatic flame temperature, are higher for the H₂/Cl₂ reaction compared to the CH₄/air combustion. By studying the influence of H₂O and HCl as inert components it was shown by numerical investigations that the maximum temperature could be decreased to a level, which makes the usage of a porous reactor feasible. A porous reactor for laboratory use was tested with O₂/CH₄/N₂ combustion, which delivers even higher adiabatic temperatures and flame speeds than the H₂/Cl₂ reaction. Finally, experiments with H₂/Cl₂/HCl reaction were carried out and first results are presented.     

Two-stage cyclic ammonium sulfate roasting and leaching of extracting vanadium and titanium from vanadium slag

Compared with traditional sodium or calcification roasting process for vanadium extraction from raw vanadium slag (V-slag), ammonium sulfate (AS) roasting could reduce about 470℃ roasting temperature and avoid Cl₂, HCl, sodium-containing waste-water and waste gypsum discharging. To reduce the amount of AS added in vanadium extraction process, an efficient AS two-stage cyclic roasting and acid leaching process was proposed. The result of TG analysis indicates V-slag could be decomposed in 275-380℃ using AS roasting process. Using 2.03:1 total mass ratio of AS to V-slag, 90.86% V and 80.54% Ti could be extracted after 380℃ roasting for 30 min and 8% initial concentration of H₂SO₄ leaching at 70℃ for 100 min. XRD analysis indicates V-containing spinel phase in the 1st stage leaching residue would be efficiently decomposed by the cyclic two-stage roasting and leaching process. Furthermore, the valence of V(III) in raw V-slag was not changed after the 1st AS roasting stage, but a part of V(III) in the 1st leaching residue was oxidized to V(V) after 2nd roasting process.     

气凝胶骨架镶嵌的CeO2纳米团簇催化氧化HCl制Cl2

采用一步溶胶-凝胶法制备了镶嵌于气凝胶骨架内的CeO₂纳米团簇催化材料(CeO₂@M_xO_y, M_xO_y= SiO₂、ZrO₂、Al₂O₃)用于HCl催化氧化反应。镶嵌于气凝胶骨架内的CeO₂纳米团簇显著的量子尺寸效应导致其表现出不同于晶相CeO₂的特性,H₂-TPR测试结果显示在晶相CeO₂表面氧物种还原温区内CeO₂纳米团簇即可被充分还原。优异的氧化还原性能导致CeO₂@M_xO_y在HCl氧化过程具有良好的催化活性,其中,40CeO₂@SiO₂的活性最高,在接触时间为0.1598 h,V_O2/V_HCl为1,430℃时,Cl₂空时产率可以达到2.10 g·(g cat)^-1·h^-1。催化剂表面的HCl氧化反应同时受O₂分压和HCl分压的影响,这表明Cl₂从催化剂表面的脱附是该反应的决速步骤。     

二次反应最小条件下聚氯乙烯塑料脱氯过程的实验

采用金属网反应器对PVC热解过程中温度范围300～800℃、升温速率1～1000 K·s^-1、停留时间0～120 s的热解气体释放特性开展了实验研究.并基于EPA-26A标准对热解气中HCl和Cl₂进行了检测.结果显示,HCl和Cl₂的产率均随着温度的升高、停留时间的增长而有所提高.降低升温速率能够提升气态产物总体产率但没有改变含氯气体的总体分布.热解实验中气态产物均以HCl为主,并伴随有少量的Cl₂生成;该结果也证实了在PVC热解脱氯过程中大量含氯自由基的存在,进一步证实了PVC热解过程遵循的是自由基链反应机理.此外,通过对PVC热解焦样的分析进一步发现PVC热解第一阶段链反应终止时的分子更接近于直链多烯烃结构而非聚合环状结构,环化反应在该阶段并未发生.     

基于CFD模拟的臭氧低温氧化烧结烟气中NO过程分析

以256 m²烧结机O₃氧化烧结烟气中NO过程为研究对象,采用CFD数值模拟方法考察了含O₃喷射气体与烧结烟气流动及NO低温氧化特性。通过与76步复杂反应机理的对比验证了11步简化机理的适用性,分析了反应温度、O₃/NO摩尔比以及O₃分布特性对NO氧化效率和不同价态NO _x 转化率的影响规律。通过对简单结构反应器的模拟结果表明：NO₃稳定性较差,烟道内主要氧化产物为NO₂与N₂O₅;随反应温度升高,NO氧化效率基本保持不变,NO₂转化率提高且提升速率逐渐增大而N₂O₅呈相反规律;随O₃/NO摩尔比增大,NO氧化效率提高但提升速率逐渐减小,NO₂转化率先增大后在摩尔比高于1.25时开始减小,而各工况均产生N₂O₅且生成量逐渐增大,其原因为射流核心区可提供高O₃/NO摩尔比条件;通过优化O₃分布器结构改善O₃与烟气接触与混合条件,O₃与NO摩尔比为1.0、停留时间为0.87 s时NO氧化率可提高约12.8%,摩尔比为2.0、停留时间为1.73 s时N₂O₅转化率可提高约15.6%。     

十水草酸铈的热分解过程以及热分解动力学研究

利用TG-DSC法研究了十水草酸铈在N2和O2氛围下煅烧过程的差异及其分解动力学机理.结果表明,十水草酸铈在N2气氛下煅烧时,煅烧产物CeO2表面附着有黑色的炭黑,而在O2气氛下煅烧时,仅得到浅黄色的CeO2.依据实验结果推测,十水草酸铈在N2气氛下煅烧时经历3步热分解过程;而在O2气氛下煅烧时经历2步分解过程,第1步...     

Fabrication of ferroelectric lead iron tungstate ceramics via a two-stage solid-state reaction

Ferroelectric Pb(Fe_2/3W_1/3)O₃ was synthesized via a new two-stage solid-state reaction discussed in the present study. This method utilized Fe₂WO₆ prepared at the first-stage which subsequently reacted with a stoichiometric amount of PbO at the second stage. This process efficiently suppressed the formation of lead tungstates and liquid phases; in addition, pyrochlore phase was formed as the only intermediate compound. A substantial amount of pyrochlore phase was converted to Pb(Fe_2/3W_1/3)O₃ at around 710 °C associated with an endothermic reaction. On heating up to 750 °C over 99% perovskite Pb(Fe_2/3W_1/3)O₃ was formed, and this formation became complete at 840 °C. Compared with the conventional solid-state reaction, this process not only simplified the formation process, but also reduced the formation temperature of Pb(Fe_2/3W_1/3)O₃. The crystal structure of Fe₂WO₆ did not significantly influence the formation mechanism; whereas, the morphology of Pb(Fe_2/3W_1/3)O₃ was markedly affected by the grain size of Fe₂WO₆. By using this process, pure Pb(Fe_2/3W_1/3)O₃ with a submicron microstructure was successfully fabricated.     

生物质锅炉氯腐蚀的密度泛函理论研究

氯气的活化氧化腐蚀是生物质锅炉过热器腐蚀的主要原因之一。为探究活化氧化腐蚀循环中FeCl₂与O₂的反应机理,本文利用Material Studio中的DMOl³模块,基于密度泛函和过渡态理论,优化了各反应物、产物、中间体和过渡态的几何构型。通过频率分析证实了中间体和过渡态的真实性。结果表明,FeCl₂与O₂反应生成Fe₃O₄的过程中逐次生成3个Cl₂分子,其中第三个Cl₂逸出生成Fe₃O₄需要吸收高达300.4 kJ/mol的能量,为反应路径的速率决定步骤。     

Gas-phase photocatalytic degradation of trichloroethylene on pretreated TiO2

This paper reports the effects of preillumination, prechlorination and prehydroxylation of TiO₂ glass fiber cloth (TiO₂-GFC) on the photocatalytic degradation (PCD) reaction of trichloroethylene (TCE) in gas–solid regime. The reaction was monitored in situ by FT-IR spectroscopy at room temperature (298 K). Product analysis by gas chromatography–mass spectrometry (GC–MS) revealed the formation of a new by-product, 1,1-dichloroethane (1,1-DCE) in significant amount along with other known by-products. The photocatalytic activities of TiO₂-GFC and the mineralization of TCE were dependent on preillumination, prehydroxylation and prechlorination while the product yield was significantly influenced by prehydroxylation and prechlorination of TiO₂-GFC. Prechlorination increased the yields of phosgene (COCl₂) and pentachloroethane (C₂HCl₅) while prehydroxylation decreased the yield of COCl₂ with corresponding increases in the yield of oxalyl chloride (COClCOCl) and the mineralization of TCE, suggesting a possible surface-mediated hydrolysis of phosgene to COClCOCl in the latter case. Reaction schemes have been proposed to account for the formation of 1,1-DCE and COClCOCl. The photocatalytic activity of TiO₂-GFC and the mineralization of TCE have been found to correlate with the concentration of HCl employed for the prechlorination of TiO₂-GFC.     

Comparative study of the oxidative decomposition of trichloroethylene over H-type zeolites under dry and humid conditions

H-type zeolites (H-Y, H-ZSM-5, and H-MOR) have been investigated for the catalytic oxidative decomposition of trichloroethylene under dry and humid (1000, 7500 and 15,000 ppmv of water) conditions, between 200 and 550°C. The activity order was found to be: H-MOR>H-ZSM-5>H-Y. Temperature-programmed desorption of ammonia and diffuse reflectance FT-IR measurements of adsorbed pyridine revealed that strong Brønsted acidity plays an important role in controlling the oxidative activity of the H-type zeolites. The main oxidation products were CO, CO₂, HCl and Cl₂. Small amounts of tetrachloroethylene were also detected.

The addition of water to the feed stream did not alter the activity order of the zeolites observed in dry conditions. Better conversions were anticipated over H-MOR and H-ZSM-5 at low temperatures and excess of water concluding that both oxygen and water accounted for the TCE destruction. In contrast, H-Y showed a low activity in humid air due to its strong hydrophilic character. It was found that water promoted the formation of CO₂ and limited the generation of undesired chlorinated by-products (Cl₂ and C₂Cl₄). XRD analysis indicated that H-ZSM-5 was the most resistant zeolite to dealumination by chlorination.