碳五烃催化裂解制取低碳烯烃反应性能及机理

以ZSM-5分子筛为催化剂,碳五烃混合物为裂解原料,考察温度及稀释比对碳五烃催化裂解制丙烯/乙烯反应性能的影响。结果表明:随温度升高碳五烷烃及烯烃的转化率均不断升高,但碳五烯烃的转化率远高于碳五烷烃的转化率。同时乙烯及丙烯的收率也随温度的升高而升高,空速3.06 h-1,分压23.24 k Pa时,分别由450℃的2.38%,8.84%升高到620℃时的13.86%和19.67%。另外,随稀释比的增加,碳五烯烃转化率,乙烯、丙烯及丁烯的收率不断下降,但C6烃的收率随稀释比的增加而升高。碳五烯烃催化裂解机理分析指出:碳五烯烃催化裂解过程中碳五烯烃在直接裂解生成乙烯和丙烯的同时,也可通过二聚成C10中间体,然后生成的C10中间体再发生顺次裂解反应。该机理应用于实验规律的解释,取得了满意的结果。     

碳四烯烃制丙烯催化剂及其工业应用

研究碳四烯烃催化裂解制丙烯BOC-1催化剂的放大制备及其工业应用,详细介绍催化剂放大制备后实验室小试和工业应用评价结果。BOC-1催化剂在工业生产装置中运行和再生性能良好,丙烯单程收率28.5%,碳四烯烃转化率82.1%,催化剂使用周期17天,各项性能指标均超过洛阳炼化宏力化工有限责任公司的工业催化剂水平,适合进一步推广使用。建立由烯烃催化裂解、吸收稳定、气分、MTBE醚化和烷烃分离5个单元组成的碳四烯烃资源综合利用工艺流程,并使用VMGSim流程模拟软件进行模拟计算。结果表明,采用新工艺流程,碳四烯烃综合利用率99.3%,聚合级丙烯收率35.19%。     

碳四烯烃催化裂解制乙烯和丙烯热力学分析及反应性能考察

以C2~C4烯烃作为碳四烯烃催化裂解制乙烯和丙烯反应系统模型,借助吉布斯自由能最小原理对碳四烯烃裂解过程进行热力学计算。结果表明,随着温度升高,乙烯平衡收率升高,610℃时,丙烯平衡收率达44.8%。在丁烯裂解过程中,随着压力降低,乙烯平衡收率升高,压力低于0.1 MPa时,随着压力降低,乙烯平衡收率升高速率加快,由0.1 MPa时的21.8%升至0.01 MPa时的46.5%。压力在(0.05~0.8)MPa时,随着压力降低,丙烯平衡收率缓慢升高,0.05 MPa时达45%,之后迅速下降。热力学计算结果与实验结果比较显示,实验温度范围,1-丁烯在ZSM-5分子筛催化剂上催化裂解过程中乙烯和丙烯的收率以及丁烯转化率随温度的变化趋势同热力学计算结果一致。从提高丙烯收率的角度,建议温度(500~580)℃,压力0.05 MPa。     

富集石脑油中正构烷烃,降低乙烯原料及能耗

考察了裂解原料中不同正构烷烃浓度对裂解乙烯、丙烯和丁二烯收率的影响.裂解产物中乙烯、丙烯和丁二烯收率均与裂解原料中正构烷烃的浓度在一定范围内呈现良好的线性关系.裂解烯烃收率随裂解原料中正构烷烃浓度增加而提高,但当正构烃浓度超过90%时,裂解烯烃收率随正构烃浓度增加的趋势变缓.吸附分离适宜的分离精度为生产正构烷烃含量为90%左右的脱附油作为乙烯裂解原料,吸余油作为催化重整原料或高辛烷值汽油调和组分.本文对90万吨乙烯裂解装置的原料调配方案进行了初步探讨,同时对固定床和模拟移动床两种石脑油吸附分离工艺进行了对比.     

轻烃催化裂解制低碳烯烃反应规律与原料特征化

利用小型固定床实验装置对比研究了轻烃模型化合物的催化裂解性能,从优到劣的顺序依次是正构烯烃、正构烷烃、环烷烃、异构烷烃、芳香烃。正构烷烃、异构烷烃与环烷烃催化裂解的总低碳烯烃收率有较大差别,但是总低碳烯烃选择性却均在56.57%左右。研究了直馏石脑油的催化裂解性能,发现乙丙烯收率和总低碳烯烃收率随反应温度的升高及重时空速的降低而逐渐增大;在反应温度680℃、重时空速4.32 h-1和水油稀释比0.35的条件下,乙丙烯收率35.87%(质量),总低碳烯烃收率为41.94%(质量)。针对轻烃催化裂解提出了原料特征化参数KF,它是原料H/C原子比、相对密度与分子量的函数,能较好地表征轻烃原料的催化裂解性能。     

典型烃类分子裂解产物分布数值模拟

利用烃类蒸汽热裂解二维工艺数学模型,选择二维模型原料分子中13种典型烃类分子,通过数学模拟考察烃类分子结构和裂解温度对热裂解产物的影响.结果表明:正构烷烃裂解产物中乙烯收率明显大于异构烷烃,且乙烯收率随着烷烃碳数的增加逐渐增加;异构烷烃裂解产物中丙烯收率大于同碳数的正构烷烃,且丙烯收率随碳数增大而显著减少;异构烷烃裂解...     

轻烃催化裂解制低碳烯烃反应规律与原料特征化

利用小型固定床实验装置对比研究了轻烃模型化合物的催化裂解性能,从优到劣的顺序依次是正构烯烃、正构烷烃、环烷烃、异构烷烃、芳香烃。正构烷烃、异构烷烃与环烷烃催化裂解的总低碳烯烃收率有较大差别,但是总低碳烯烃选择性却均在56.57%左右。研究了直馏石脑油的催化裂解性能,发现乙丙烯收率和总低碳烯烃收率随反应温度的升高及重时空速的降低而逐渐增大;在反应温度680℃、重时空速4.32 h^-1和水油稀释比0.35的条件下,乙丙烯收率35.87%（质量）,总低碳烯烃收率为41.94%（质量）。针对轻烃催化裂解提出了原料特征化参数KF,它是原料H/C原子比、相对密度与分子量的函数,能较好地表征轻烃原料的催化裂解性能。     

SAPO-34催化剂上C4烯烃催化裂解与甲醇转化制烯烃反应耦合

采用SAPO-34催化剂,在流化床装置上考察了甲醇制烯烃(MTO)副产C4烯烃催化裂解制乙烯和丙烯的反应行为,分析了C4烯烃转化率、产物收率等主要指标随工艺参数的变化规律,对比了C4烯烃催化裂解和MTO反应积炭催化剂的差异,提出了C4烯烃催化裂解适宜的关键工艺条件。C4烯烃催化裂解对比MTO反应需要较高的反应温度和催化剂活性。结果表明,C4烯烃裂解反应过程形成的积炭催化剂仍可用于MTO反应,并且具有较高的甲醇转化率和低碳烯烃选择性,因此可以采用SAPO-34催化剂把两个独立的反应串联耦合在一起。     

催化裂化干气与混合C4组合进料制丙烯的研究

基于提高烯烃利用率和增产丙烯的目的,以催化裂化(FCC)干气和混合C4组合原料来制备丙烯,考察了混合比例、空速、反应温度等因素对产物分布的影响。结果发现,当以生产丙烯为目的时,混合比例和空速分别为3.3和118 m in-1时,丙烯收率可获得最大值33.2%(质量分数)。在350~675℃内,随温度升高,裂解深度增加,乙烯、丙烯等小分子烯烃含量增加,丁烯含量则是先减小,当温度高于600℃时又有所回升,推测高温下丁烷为烯烃的生成做了一部分贡献。     

USC裂解炉出口温度、炉管构型对循环乙烷裂解性能的影响

在USC裂解炉上进行了不同乙烯原料、裂解炉出口温度、炉管构型的工业裂解标定试验,结果表明,循环乙烷易脱氢生成大量的乙烯(56.35%),丙烯、丁二烯、裂解液相产物收率极低,液化气通过断链反应可生成乙烯、丙烯、丁二烯以及少量的裂解液相产物,石脑油拔头油裂解乙烯收率低,但裂解液相产物(高附加值)收率较高;乙烷裂解炉出口温度宜控制在858℃左右;与U型炉管相比,乙烷在M型炉管裂解乙烷转化率、乙烯收率、丙烯收率、三烯收率高。     

甲醇制对二甲苯联产低碳烯烃改性ZSM-5催化剂在流化床中的反应性能

在流化床反应器中，对Zn、Si和P改性的ZSM-5催化剂的甲醇制对二甲苯联产低碳烯烃的反应性能进行了研究。采用X射线衍射（XRD）、BET比表面积、扫描电镜（SEM）、NH₃-程序升温脱附（NH₃-TPD）等手段进行表征分析。结果表明，Zn改性使得催化剂酸强度降低，中强酸酸量增加，对二甲苯和低碳烯烃选择性都随之提高；一定量的硅沉积改性在降低催化剂外表面酸量的同时缩小孔口，浸渍适量P能够调变分子筛的酸中心强度和酸量，这都能够提高对二甲苯选择性。在流化床反应器中甲醇制对二甲苯联产低碳烯烃反应结果表明，3Zn-3Si-3P/ZSM-5催化剂在温度425℃、常压、反应时间40min、空速1h^-1的条件下，对二甲苯在二甲苯中的选择性为76.0%，C₂~C₄低碳烯烃选择性为24.4%，特别是芳烃和C₂~C₄低碳烯烃的总选择性高达92.2%。     

载体对Li-Mn氧化物催化甲烷氧化偶联反应作用

采用浸渍法制备不同金属氧化物载体负载的Li-Mn/MO_x(M=Mg,La,Ti,Si,Zr,Ta)催化剂,对其甲烷氧化偶联反应活性进行评价。结果表明,以TiO_2为载体制备的Li-Mn/TiO_2催化剂具有较高的CH_4转化率和C2烃选择性,C_2烃产率显著提高,金属氧化物TiO_2是Li-Mn复合氧化物的优良催化剂载体。n(Li)∶n(Mn)=1.0∶2.0形成的Li-Mn/TiO_2催化剂具有最高的CH_4转化率和C_2烃选择性,n(C_2H_4)∶n(C_2H_6)的增加有助于提高反应产物中C_2H_4的相对浓度,W元素的添加未能进一步提高Li-Mn/TiO_2催化剂的催化活性。Li-Mn/TiO_2催化剂在n(Li)∶n(Mn)=1.0∶2.0、反应温度775℃、反应压力0.1 MPa、V(CH_4)∶V(O_2)=2.5、空速7 200 m L·(h·g)~(-1)和催化剂用量0.5 g条件下,CH_4转化率达31.9%,C_2选择性达52.7%,表现出最佳催化效果。     

碳二前脱丙烷前加氢催化剂工艺条件试验

采用浸渍法制备Pd-Ag/α-Al2O3催化剂,采用碳二前脱丙烷前加氢工艺系统考察反应器入口温度、空速和反应压力对催化剂性能的影响。结果表明,随着反应器入口温度升高,乙炔和丙炔+丙二烯转化率提高,乙烯选择性提高至一定值后趋于稳定,丙烯选择性波动不大,正丁烯生成量增加,较为适宜的反应器入口温度为(60~70)℃;随着空速升高,乙炔和丙炔+丙二烯转化率降低,乙烯选择性提高,丙烯选择性变化不大,正丁烯生成量降低,较为适宜的空速为(12 000~14 000)h-1;随着反应压力升高,乙炔转化率和丙炔+丙二烯转化率略增,乙烯选择性降低,较为适宜的反应压力为3.6 MPa。     

Light olefin production by catalytic co-cracking of Fischer–Tropsch distillate with methanol and the reaction kinetics investigation

Catalytic co-cracking of Fischer–Tropsch(FT) light distillate and methanol combines highly endothermic olefin cracking reaction with exothermic methanol conversion over ZSM-5 catalyst to produce light olefins through a nearly thermoneutral process. The kinetic behavior of co-cracking reactions was investigated by different feed conditions: methanol feed only, olefin feed only and co-feed of methanol with olefins or F–T distillate. The results showed that methanol converted to C_2–C_6 olefins in first-order parallel reaction at low space time, methylation and oligomerization–cracking prevailed for the co-feed of methanol and C_2–C_5 olefins, while for C_6–C_8 olefins,monomolecular cracking was the dominant reaction whether fed alone or co-fed with methanol. For FT distillate and methanol co-feed, alkanes were almost un-reactive, C_3–C_5 olefins were obtained as main products, accounting for 71 wt% for all products. A comprehensive co-cracking reaction scheme was proposed and the model parameters were estimated by the nonlinear least square method. It was verified by experimental data that the kinetic model was reliable to predict major product distribution for co-cracking of FT distillate with methanol and could be used for further reactor development and process design.     

The simultaneous activation of methane and carbon dioxide to C2 hydrocarbons under pulse corona plasma over La2O3/γ-Al2O3 catalyst

The pulse corona plasma has been used as an activation method for reaction of methane and carbon dioxide, the product was C₂ hydrocarbons and by-products were CO and H₂. Methane conversion and the yield of C₂ hydrocarbons were affected by the carbon dioxide concentration in the feed. The conversion of methane increased with increasing carbon dioxide concentration in the feed whereas the yield of C₂ hydrocarbons decreased. The synergism of La₂O₃/γ-Al₂O₃ and plasma gave methane conversion of 24.9% and C₂ hydrocarbons yield of 18.1% were obtained at the power input of plasma was 30 W. The distribution of C₂ hydrocarbons changed by using Pd-La₂O₃/γ-Al₂O₃ catalyst, the major C₂ product was ethylene.     

全结晶ZSM-5分子筛催化剂研究及工业应用

制备了全结晶ZSM-5分子筛催化剂,采用XRD、SEM、N2物理吸附-脱附及NH3-TPD等对催化剂进行表征,并考察其用于碳四烯烃催化裂解制丙烯(OCC)反应的催化性能。结果表明,制备的全结晶ZSM-5分子筛催化剂比常规成型的催化剂具有更高的结晶度、更大的比表面积、更丰富的孔结构以及更多的活性中心。高空速有利于反应的进行,提高压力对反应不利,升高温度有利于提高产物丙烯收率。在实验室研究的基础上,将全结晶ZSM-5分子筛催化剂用于OCC工业装置,取得良好的应用效果。     

Enhancement of acetylene and ethylene yields in partially decoupled oxidation of ethane by changing the composition of heat carrier

In our previous work, a partially decoupled process (PDP) was proposed for efficient conversion of ethane to increase the ethylene yield and a new structural reactor called forward-impinging-back reactor (FIB) was proposed for scale-up. In this work, the influence of changing the composition and temperature of the heat carrier was investigated by simulations with detailed chemistry to further increase of the C₂ (C₂H₂ + C₂H₄) yield in the PDP of ethane. At ideal mixing conditions, the C₂ yield is 75.3% without steam addition and it is 82.9% at steam addition ratio of β=1.4. In comparison, the C₂ yield in an FIB reactor is 62.4% without steam addition and it increases to 78.5% with steam addition (β=1.4). The requirement of high mixing efficiency is diminished by steam addition, which is favorable for reactor scale-up.     

等离子体与Cu-Pd/S-1催化剂协同催化甲烷转化制低碳烯烃

采用等体积浸渍法制备了Pd、Cu-Pd改性的S-1催化剂,利用介质阻挡放电（DBD）等离子体反应器研究了甲烷无氧转化制低碳烯烃（C₂~C₄⁼）的性能,重点关注了乙烯的产量。探讨了Ar的添加和特定输入能量（SIE）对甲烷转化率以及产物分布的影响。实验结果表明,等离子体与催化剂协同催化与仅使用等离子体相比性能更优异,使乙烯选择性提高了3.1倍,C₂~C₄⁼的选择性提高了2.7倍;与S-1相比,Pd/S-1具有更高的乙烯选择性,这是因为在S-1上负载金属Pd有助于乙炔原位加氢生成乙烯;适宜的Pd负载量有利于提高烯烃选择性,而过高的Pd负载量倾向于不饱和烃的连续加氢,导致了烷烃的生成;与单金属Pd改性相比,Cu-Pd双金属改性抑制了乙烯的进一步加氢,提高了乙烯的选择性。通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）、高倍透射电子显微镜（HRTEM）、X射线粉末衍射（XRD）、X射线光电子能谱（XPS）对催化剂进行了表征分析。结果表明,Cu的加入使自身电子向Pd转移,增加了Pd电子密度;另外,Cu的存在提高了Pd的分散性。以2Cu-0.1Pd/S-1为催化剂时可以得到更优异的反应性能。     

A LUMPED KINETIC MODEL FOR DEHYDRATION OF ETHANOL TO HYDROCARBONS OVER HZSM-5

A kinetic model for the conversion of ethanol to hydrocarbons over HZSM-5 catalyst has been developed. The model is based on data from ethanol dehydration experiments conducted in a fixed-bed integral reactor at atmospheric pressure and temperatures of 150°C to 360°C, and is the first which integrates the major reaction pathways of both dehydration and higher hydrocarbon formation over ZSM-5 zeolite. In the model C₃-C₆ olefins, C₃-C₅ paraffins, and C₆⁺ hydrocarbons are treated as lumped species, while ethanol, diethyl ether, ethylene, and ethane are treated individually. Nonlinear parameter estimation using quasilinearization and least squares as the objective function has been implemented to estimate rate constants, adsorption equilibrium constants, and activation energies. The Langmuir-Hinshelwood rate expressions successfully correlated the experimental data.     

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.