乙醇耦合制备C4烯烃影响因素的研究

C₄烯烃在化工产品及医药生产领域具有非常广泛的运用，乙醇是生产制备C₄烯烃的原料，在制备过程中，催化剂组合与温度对C₄烯烃的选择性和C₄烯烃收率将产生影响。本文就Co/SiO₂和HAP装料比、每分钟乙醇注入量以及温度对C₄烯烃收率产生影响三种主要因素进行了不同的组合，利用Spearman秩相关分析法研究了不同装料方式下的影响因子与C₄烯烃收率的依赖级别，分别以乙醇流量和C₄烯烃选择性为因变量，催化剂种类和温度为自变量建立了基于最小二乘法的多元线性回归模型，并利用鲨鱼优化算法在可行域内求得C₄烯烃收率的最优值为4 994.349 862‰。     

混合C4作乙烯原料的研究及经济性分析

以混合C₄作乙烯裂解原料,通过GK-Ⅵ型蒸汽裂解炉分别进行了4个不同稀释比(水和物料的质量比)及裂解温度评价试验,并进行未加氢混合C₄与加氢混合C₄裂解性能对比评价实验。结果表明,在裂解温度为838℃、反应压力为0.085 MPa、稀释比为0.55的条件下,加氢混合C₄三烯收率大于50%,并且经济效益达到最大,为最佳裂解条件。加氢混合C₄可以作为原料蒸汽裂解制烯烃的有效补充。     

ZSM-5分子筛酸性能和孔结构的协同作用对C5烯烃催化裂解性能的影响

采用不同浓度碱液处理制备了具有不同酸性质的多级孔HZSM-5分子筛，并考察其酸性能与孔结构变化对催化裂化(FCC)汽油中C₅烯烃催化裂解性能的影响。利用X射线衍射(XRD)、N₂吸附脱附、氨气程序升温脱附技术(NH₃-TPD)、吡啶红外(Py-IR)和扫描电镜(SEM)等表征手段研究了HZSM-5分子筛的结构、形貌、酸性质和孔道性能。研究结果表明，适宜浓度的碱液处理可以提高HZSM-5分子筛的强Br?nsted (B酸)酸量和介孔体积，显著提高C₅烯烃转化率和乙烯、丙烯的收率。当碱液浓度为0.2 mol·L^-1,HZSM-5分子筛强B酸中心和介孔体积之间的协同作用促进了C₅烯烃的高效转化，转化率为84.8%(质量分数)，乙丙烯总收率为86.0%(质量分数)，分别比未处理的HZSM-5分子筛增加4.4%和15.5%。     

多元线性回归模型下C4烯烃制备实验参数的优化

乙醇偶合制备C₄烯烃实验中,反应温度和催化剂组成,影响着乙醇转化率和C₄烯烃的选择性。基于大连理工大学化学实验室针对不同催化剂组成及在不同温度下获得的一系列实验数据,研究了乙醇转化率和C₄烯烃的选择性与温度的关系,建立了乙醇转化率和C₄烯烃的选择性与催化剂组成以及反应温度的多元线性回归模型。最后,以C₄烯烃收率为目标函数,将催化剂组成及反应温度作为约束条件,利用模拟退火算法,得到了最佳催化剂组成及反应温度。     

联合发射光谱与动力学计算的非热等离子体重整CO2-CH4机理

非平衡等离子体重整CO₂-CH₄制合成气是实现2种温室气体资源化利用的新兴技术途径。综合采用发射光谱分析、反应动力学计算和连续质谱对常温常压介质阻挡放电(DBD)非热等离子体重整CO₂-CH₄反应途径进行探索。比功率S_EI为52 J/cm³时,可得到CH₄和CO₂转化率最大分别为22.8%和9.4%。稳态气相产物连续质谱在线分析表明,C₂H₄为C₂烃生成重要中间体,CH₄比例越高C₂烃生成量越大,且按C₂H₆2H₄2H₂顺序升高。发射光谱检测到·CH、·C₂自由基和CO、CO■特征谱线,·CH相对强度随比功率增加明显降低,CO■相对强...     

液化气C4组分异构化研究及应用

在实际生产过程中,MTBE装置加工后的剩余C₄中含有大量非活性C₄烯烃,该部分烯烃随着液化气作为产品进行销售,对于液化气中的C₄造成浪费。提出将MTBE装置剩余C₄引入汽油加氢醚化装置异构化反应器进行异构化反应,将剩余C₄中的非活性烯烃转化为活性烯烃,再将异构化产物送至MTBE装置原料缓冲罐中作为MTBE装置原料进行反应。通过调研后得出,异构化反应器催化剂对剩余C₄中的非活性烯烃转化率可达30%,异构化反应产物与进料对比,异丁烯含量上升约3%,可有效提高MTBE装置产品产量。     

甲醇制烯烃技术进展

阐述了甲醇制低碳烯烃各个工艺的研究进展,从甲醇制乙烯、甲醇制丙烯和甲醇制丁烯三个方面对比了各自技术特点,指出未来需开发出以丙烯、 C₄烯烃为主产品的新技术。     

不同氧浓度下煤挥发分燃烧的化学动力学研究

燃煤有机污染物对人类健康和生态环境存在严重危害,而O₂对火焰中有机产物的形成具有明显的调控作用。鉴于煤挥发分燃烧是燃煤过程中至关重要的一环,本文以煤热解气为燃料,通过数值模拟研究了氧化剂侧O₂浓度对对冲扩散火焰中碳氢产物生成特性和机制的影响。结果表明,O₂浓度升高促进了O和OH的生成,进而提高H浓度,突显了含H和OH参与的反应的重要性。此外,乙炔(C₂H₂)、丙炔(PC₃H₄)、炔丙基(C₃H₃)、乙烯基乙炔(C₄H₄)、苯(C₆H₆)和萘(C₁₀H₈)的浓度均增大。增加O₂浓度促进了C₂H₂向PC₃H₄的转化,并使得C₃H₃更倾向于转化为丁二烯(C₄H₆),而富烯更倾向于通过苯基(C₆H₅)生成C₆H₆,因此C₆H₅作为C₆H₆前体的地位被加强。     

不同氧浓度下煤挥发分燃烧的化学动力学研究

燃煤有机污染物对人类健康和生态环境存在严重危害,而O₂对火焰中有机产物的形成具有明显的调控作用。鉴于煤挥发分燃烧是燃煤过程中至关重要的一环,本文以煤热解气为燃料,通过数值模拟研究了氧化剂侧O₂浓度对对冲扩散火焰中碳氢产物生成特性和机制的影响。结果表明,O₂浓度升高促进了O和OH的生成,进而提高H浓度,突显了含H和OH参与的反应的重要性。此外,乙炔(C₂H₂)、丙炔(PC₃H₄)、炔丙基(C₃H₃)、乙烯基乙炔(C₄H₄)、苯(C₆H₆)和萘(C₁₀H₈)的浓度均增大。增加O₂浓度促进了C₂H₂向PC₃H₄的转化,并使得C₃H₃更倾向于转化为丁二烯(C₄H₆),而富烯更倾向于通过苯基(C₆H₅)生成C₆H₆,因此C₆H₅作为C₆H₆前体的地位被加强。     

C5/C6异构化和正异构分离技术经济分析

我国汽油组分中催化裂化汽油占比大，造成汽油池中烯烃、芳烃含量偏高。随着车用汽油质量标准升级，要求汽油池调和一定比例非芳烃、烯烃的烷基化油或甲基叔丁基醚(MTBE)等组分，提高了生产成本。C₅/C₆轻石脑油作为一种低价值的烷烃组分，可以调和汽油池芳烃和烯烃含量，但辛烷值偏低，将其转变成富含异构烃的高辛烷值汽油调和组分，可有效提高企业经济效益。文章对C₅/C₆轻石脑油通过异构化或正异构分离技术提高辛烷值后调入汽油池的技术经济性进行对比分析，为企业进行技术选择提供了参考借鉴。     

Direct synthesis of middle iso-paraffins from synthesis gas on hybrid catalysts

This paper focuses on the synthesis of iso-paraffin-rich hydrocarbons by Fischer–Tropsch synthesis (FTS) over silica gel supported Co catalyst (Co/SiO₂). The basic concept is to isomerize and/or hydrocrack the primary FTS hydrocarbon products. A physical mixture consisting of a small amount of zeolite or Pd/zeolite mixed with Co/SiO₂ enhanced the formation of C₄–C₁₀ iso-paraffins while suppressing the formation of higher molecular hydrocarbons, probably because of the selective cracking of these hydrocarbons on them. In separate experiments, a two-reactor system was used. The first reactor contained a physical mixture of Co/SiO₂ and zeolite, and the second reactor contained zeolites or Pd-supported zeolites. The two-reactor system gave sharp C-number distribution within C₃–C₆ and iso-paraffins-rich products. The hydrocracking of n-octane and n-decane (model compound simulating products of the FTS reaction) over mixed catalysts composed of various compositions of Pd/SiO₂ and ZSM-5 in the presence of gaseous hydrogen showed high and stable activity, and produced primarily iso-paraffin-rich hydrocarbons. The isomerization was favored for mixtures rich in Pd/SiO₂. The role of Pd was thought to be the inlet of hydrogen spillover to the zeolite surface.     

碳五烃催化裂解制取丙烯/乙烯反应性能

以ZSM-5分子筛为催化剂,碳五烃混合物为裂解原料,考察空速对碳五烃催化裂解制丙烯/乙烯反应性能的影响。结果表明,在580℃和实验空速范围,随着空速的增加,碳五烷烃及烯烃转化率整体呈下降趋势,但碳五烯烃转化率远高于碳五烷烃。乙烯及丙烯收率在空速3 h-1时达到最大,分别为10.51%和13.02%。碳四烯烃收率随空速的升高而降低,但各丁烯异构体相对于总烯烃的质量分布接近热力学平衡态。     

Chemical Effects of CO2 Concentration on Soot Formation in Jet-stirred/Plug-flow Reactor

Soot formation was investigated numerically with CO2 addition in a jet-stirred/plug-flow reactor （JSR/PFR） C2H4/OJN2 reactor （C/O ratio of 2.2） at atmospheric pressure. An updated Kazakov mechanism empha- sizes the effect of the O2/CO2 atmosphere instead of an O2/N2 one in the premixed flame. The soot formation was taken into account in the JSR/PFR for C2H4/O2/N2. The effects of CO2 addition on soot formation in different C2H4/O2/CO2/N2 atmospheres were studied, with special emphasis on the chemical effect. The simulation shows that the endothermic reaction CO2 ＋ H - CO ＋ OH is responsible of the reduction of hydrocarbon intermediates in the CO2 added combustion through the supplementary formation of hydroxyl radicals. The competition of CO2 for H radical through the above forward reaction with the single most important chain branching reaction H ＋ O2, ＇ O ＋ OH reduces significantly the fuel burning rate. The chemical effects of CO2 cause a significant increase in residence time and mole fractions of CO and OH, significant decreases in some intermediates （H, C2H2）, polycyclic aromatic hydrocarbons （PAHs, C6H6 and CI6H10, etc.） and soot volume fraction. The CO2 addition will leads to a decrease by only about 5% to 20% of the maximum mole fractions of some C3 to Clo hydrocarbon intermediates. The sensitivity analysis and reaction-path analysis results show that C2H4 reaction path and products are altered due to the CO2 addition.     

CO/CO2加氢高选择性合成化学品和液体燃料

一氧化碳/二氧化碳（CO/CO₂）转化利用是碳一化学与CO₂捕集利用中的重要环节,也是当今碳资源的非石油路线利用最具挑战性的方向之一。CO₂的高效活化与定向转化是CO₂利用过程中的关键问题,而CO加氢转化最大的瓶颈问题为如何有效控制C-O键的活化、C—C键的形成、碳链增长及终止。本文主要综述 CO/CO₂加氢高选择性合成重要化工原料低碳烯烃（C₂ ⁼～C₄ ⁼）以及一步高效合成汽油馏分（C₅～C₁₁）等方面取得的突破性进展。目前,CO/CO₂加氢主要经过费托合成与氧化物/分子筛双功能两条路线合成低碳烯烃与汽油燃料。针对费托合成C₂ ⁼～C₄ ⁼,分析表明棱柱状碳化钴得到的烃类产物分布可以显著突破Anderson-Schulz-Flory（ASF）分布的限制,而分子筛已被广泛用于构建双功能费托催化剂,由于酸性分子筛具有加氢裂化、低聚与异构化等功能,使得CO/CO₂还可以直接高选择性地转化为C₅～C₁₁烃类。另一方面,将可以活化CO或CO₂到甲醇的可还原型氧化物与具有C—C偶联功能的SAPO-34或HZSM-5分子筛进行耦合,也可以实现CO/CO₂加氢一步合成低碳烯烃或汽油且具有非常优异的选择性和高转化率。今后,借鉴纳米合成领域新方法,使产物分布打破经典ASF限制,最大限度地提高目标烃类化合物的选择性并显著减少甲烷的生成是研究关键。     

Reaction mechanism of methane activation using non-equilibrium pulsed discharge at room temperature

The reaction mechanism of methane activation using non-equilibrium pulsed discharge was largely clarified from the emission spectroscopic study and experiments with higher hydrocarbons and some kinds of isotopes. The strong emission of atomic carbon and C₂ swan band system was observed as well as H Balmer series emission. This indicates that methane was highly dissociated into C and H by electron impact, which is consistent with the result of high C₂D₂ composition in produced acetylene when the mixture of CH₄ and D₂ was fed into discharge region. High electron energy contributed to produce atomic carbon directly from methane, and high electron density promoted the dehydrogenation from CH₃, CH₂ and CH to produce atomic carbon consecutively. The reason for the high selectivity to C₂H₂ was the high concentration of CH or C₂ formed from atomic carbon, and the repetition mechanism of decomposition and recombination among C, CH, C₂ and C₂H₂.     

离子液体/硫酸催化C4烷基化反应过程强化——表界面特性研究

利用分子动力学（MD）模拟研究了不同支链长度以及官能团的Brønsted酸性离子液体（BILs）对H₂SO₄/C₄烷烯界面特性的调控。结果表明,BILs的加入可以明显增强C₄烷烯在两相界面处的溶解和扩散,有利于烷基化油品的提升。烷基链较长的阳离子表现出较强的界面密度富集现象,并且其支链倾向于伸入C₄烷烯相,有利于界面性质的增强。阳离子支链的增长能够促进C₄烷烯的溶解,同时增大了C₄烷烯的界面存留率,不利于其界面扩散。另外,相比于非磺酸功能化离子液体（non-SFILs）,磺酸功能化离子液体（SFILs）促进了C₄烷烯的溶解,但抑制了C₄烷烯的扩散。本文在C₄烷基化界面性质方面的研究有利于深入理解C₄烷基化过程,相关结果有望为烷基化过程强化和新型催化剂的优化和设计提供帮助。     

石油化工与催化 C4馏分加氢催化剂的应用

为了提高C₄馏分的利用价值并实现扩大乙烯裂解料的来源,使用自制的镍系加氢催化剂和钴-钼-镍系加氢精制催化剂,在固定床200 mL绝热评价装置上对C₄馏分液化石油气物料进行全加氢实验,论证镍系加氢催化剂适用于含有低碳含硫化合物C₄馏分的可行性,对模拟的某化工厂C₄馏分原料进行加氢饱和性能考察,对含有高浓度双烯烃和炔烃的丁二烯抽提装置尾气进行原料模拟和全加氢评价。结果表明,自制催化剂适用于含有低碳硫化物的C₄馏分全加氢,可以处理高含双烯烃的C₄物料,并具有良好的低温活性。     

Conversion of naphthenes to a high value steamcracker feedstock using H-ZSM-5 based catalysts in the second step of the ARINO-process

Future regulations for the limitation of sulfur and aromatics in fuels driven by the European Auto Oil Program (AOP II) stimulate the need for an alternative utilization of the resulting surplus of pyrolysis gasoline (pygas). The conversion of heavy pyrolysis gasoline into valuable steam cracker feedstock with a maximum yield of C₂–C₄ n-alkanes is achieved via the ARINO^® two-step process, jointly developed by Linde, VEBA Oil and Süd-Chemie. The first step involves a hydrogenation of aromatics to naphthenes followed by the subsequent ring opening and cracking in the second step.

Süd-Chemie developed a new commercial cracking catalyst for the second step of the ARINO^® process with the aim to maximize the yield of C₂–C₄ n-alkanes at low formation of methane and aromatics. The ring opening and cracking reaction of naphthenes was studied in a bench scale tubular reactor over extruded H-ZSM-5 based zeolite catalysts.

In a series of screening tests using a commercial, hydrogenated and desulphurized heavy pyrolysis gasoline, the influence of the preparation parameters such as zeolite acidity, palladium content as well as the type of binder were investigated. Furthermore, the influence of the process conditions space velocity and temperature was studied.

High yields of C₂–C₄ n-alkanes at low formation of undesired methane and aromatics were achieved over an alumina bound zeolite with medium Brønsted acidity loaded with palladium.

The reduction of the space velocity resulted in an increase in the C₂–C₄ n-alkane yield and lower formation of aromatics, but a simultaneous increase in the methane make. Raising the temperature from 280 to 370 °C significantly increased the catalyst activity.     

Catalytic decomposition of light alkanes, alkenes and acetylene over Ni/SiO2

The decomposition of different hydrocarbons (CH₄, C₂H₆, C₂H₄, C₂H₂, C₃H₈, and C₃H₆) over Ni (5 wt.%)/SiO₂ catalysts was carried out. The initial rates of decomposition of the hydrocarbons, the kinetic curves of the decomposition and the kinetic curves of the hydrogenation of deposited carbon into methane depended on the types of hydrocarbons. In addition, the catalytic life of the Ni/SiO₂ catalyst was also dependent on the types of hydrocarbons, i.e. the life was longer according to the order, alkanes>alkenesacetylene.

The carbons deposited on the catalyst were characterized by SEM and Raman spectroscopy. The appearances of the deposited carbons were different among alkanes, alkenes, and acetylene, i.e. a zigzag fiber structure from methane, and a rolled fiber structure from alkenes and acetylene. From Raman spectra of the deposited carbons, it was found that the degree of graphitization of deposited carbon was higher in the order, alkanes>alkenes>acetylene. These results suggest that the mechanism of decomposition of hydrocarbons and the growth mechanism of carbon fibers on the catalyst were different among alkanes, alkenes and acetylene.     

混合制冷剂中重烃对天然气液化流程的影响

混合制冷剂(MR)组分是影响天然气液化流程性能的最重要因素之一。在某些特定的液化天然气(LNG)装置中,丁烷和戊烷等重组分不受欢迎。研究了以下4种混合制冷剂组分用于单混合制冷剂(SMR)流程的效果:含有异丁烷(C₄)和异戊烷(C₅)的MR;不含C₄的MR;不含C₅的MR;不含C₄和C₅的MR。对各流程的比功耗进行了对比。结果表明,相比于异丁烷,异戊烷对降低能耗的贡献更大;另外,工况1的能耗比工况4低18%。更进一步地,提出了采用不同制冷剂进行预冷的SMR流程。对于工况4,采用丙烷预冷的流程能耗可降低12%。