【作者】 王斐；

【导师】 汪文川；

【作者基本信息】 北京化工大学 ， 化学工程， 2007， 博士

【摘要】 中国石油化工集团上海石油化工研究院所开发的烯烃催化裂解技术(Olefins Catalytic Cracking Technology，OCC)是以碳四烃资源为原料增产丙烯和乙烯的新工艺，对解决国内碳四烃富集问题和提高石化企业的效益均具有极其重要的意义。因而，对碳四烃在催化裂解分子筛上的吸附和扩散研究就成为一个极具工业意义的课题。本论文针对中石化上海石油化工研究院所开发的OCC烯烃催化裂解工艺，以上海石油化工研究院所制备的用于烯烃催化裂解反应中的具有独特择形性和酸性的不同硅铝比ZSM-5分子筛催化剂为研究对象，采用实验测定、理论模型和分子模拟相结合的研究手段对碳四烃(以正丁烷和丁烯-1为代表)在ZSM-5分子筛催化剂上的吸附和扩散行为进行了广泛研究，建立了碳四烃在ZSM-5分子筛催化剂上的吸附和扩散模型。全文的主要内容和创新点如下：1．首先，通过XRD、SEM和BET测试等手段的表征，确认了上海石油化工研究院所制备提供的5种催化剂样品具有典型的ZSM-5分子筛结构；其样品晶粒晶型规整，大小均匀，晶粒分布范围较窄，晶粒尺寸在0.1～0.3μm之间，而且由于加入较大量的粘结剂导致分子筛晶粒之间形成了一部分大孔且具有较低的BET表面积。进而在上海石油化工研究院所推荐的裂解反应条件下，利用本实验室高精度的IGA-003智能重力分析仪测定了不同温度不同压力下碳四烃纯组分和不同配比混合物在具有不同硅铝比及改性组分的ZSM-5分子筛上的吸附平衡及动力学数据。2．通过对碳四烃纯组分在ZSM-5分子筛上吸附数据的关联，建立了适合于ZSM-5分子筛上碳四烃纯组分吸附的双朗格缪尔(Double Langmuir，DL)模型，以及计算得到了碳四烃在ZSM-5分子筛上的吸附热、吸附熵变和亨利常数等热力学性质，并探讨了样品硅铝比对吸附热力学性质的影响。进而将理想吸附溶液理论(Ideal Adsorbed Solution Theory，IAST)与双朗格缪尔(Double Langmuir，DL)模型相结合，提出了适用于丁烯-1(1)／正丁烷(2)混合物在ZSM-5分子筛上吸附的IAST-DL模型；并运用IAST-DL模型对丁烯-1(1)／正丁烷(2)混合物在ZSM-5分子筛上的吸附进行了广泛的研究；得到了混合物吸附选择性与样品硅铝比之间的关联方程。3．采用联合原子模型，以实验吸附热、亨利常数和吸附等温线为基础，运用与构型偏倚技术(Configurational-bias Monte Carlo，CBMC)相结合的NVT正则系统和巨正则系综模拟方法拟合得到了烃分子中联合原子与分子筛氧之间的相互作用势能参数，提出了适用于真实工业催化剂的力场参数。采用同样的模型和势能参数模拟而得到的混合物吸附等温线以及吸附选择性均与IAST-DL模型得到的计算结果相吻合。同时，对碳四烃在ZSM-5分子筛上的吸附位选择进行了研究。发现工业催化剂中大量粘结剂的加入对碳四烃分子在ZSM-5分子筛中的吸附位选择具有重大的影响作用。4．运用Fick扩散模型对碳四烃在ZSM-5分子筛上吸附动力学数据进行关联，得到了275、288及300 K下正丁烷及丁烯-1在具有不同硅铝比ZSM-5分子筛催化剂内的扩散系数，同时探讨了温度、压力以及样品硅铝比等因素对扩散系数的影响。更多还原

【Abstract】 With the C₄ olefin-rich hydrocarbons as the feed to produce ethylene andpropylene on special shape-selectivity and acidic ZSM-5 zeolite catalysts, theolefins catalytic cracking （OCC） technology developed by Shanghai ResearchInstitute of Petrochemical Technology of SINOPEC is a novel technology, andthis technology is of great importance in the utilization of C₄ olefin-richhydrocarbons and increase of benefit for petrochemical industry. Therefore, itis necessary to investigate adsorption and diffusion of C₄ hydrocarbons onZSM-5 zeolites with different Si/Al ratios, used in the catalytic crackingprocess.In this work, aimed at the OCC technology, the combine method "experiment measurement、theory model and molecular simulation" was used to study the adsorption and diffusion of C₄ hydrocarbons （n-butane and butene-1） on special shape-selectivity and acidic ZSM-5 zeolites with different Si/Al ratios used as catalysts in OCC technology, which were prepared by Shanghai Research Institute of Petrochemical Technology. The adsorption and diffusion model of C₄ hydrocarbons on ZSM-5 zeolite catalysts were proposed here. The main contents and finding are summarized as follows:1．First, five ZSM-5 zeolite samples are characterized by XRD, SEM and the nitrogen adsorption isotherm at 77 K. It is found from the XRD results that the positions of the characteristic peaks for five zeolite samples are the same with those of the standard ZSM-5 zeolite samples, indicating that the samples are all ZSM-5 zeolites. The SEM photograph shows that the ZSM-5 zeolite particulates have the regular crystal morphology and a narrow crystal size, which about is 0．1～0．3μm. As the addition of a large amount of binder, the BET surface area of five samples are all lower than that of the literature values and some macropores are formed in the ZSM-5 zeolite sample crystal particulates. Furthermore, based on the catalytic cracking conditions recommended by Shanghai Research Institute of Petrochemical Technology, the adsorption equilibrium and kinetic data of C₄ hydrocarbons on ZSM-5 zeolite with different Si/Al ratios and modified components are measured by the intelligent gravimetric analyzer （IGA-003, Hiden） at different temperatures and pressures.2．The double Langmuir （DL） model is used to correlate the equilibrium data of pure C₄ hydrocarbons on ZSM-5 zeolite samples, and the heat of adsorption, entropy change of adsorption and Henry coefficient are calculated and the affection of Si/Al ratio to adsorption thermodynamic character are discussed. Then, by combining the ideal adsorbed solution theory （IAST） with the double Langmuir （DL） model, the IAST-DL model which is capable to model the butene-1（1） /n-butane（2） mixture adsorption on different ZSM-5 zeolite samples is proposed and is used to predict the selectivities and adsorption of butene-1（1） /n-butane（2） mixture on different ZSM-5 zeolite samples covering a wide range of compositions, temperatures and pressures. The correlation between the selectivity and Si/Al ratio of sample is proposed here.3．The united-atoms （UA） representation is employed, and the interaction parameters between UA model are obtained by fitting the NVT and GCMC, which are combined with CBMC （Configurational-bias Monte Carlo） technique, simulation results with the experimental data （heat of adsorption, Henry coefficient and adsorption isotherm）. The force field parameters used for industrial catalysts are proposed here. Then, the model and force field parameters are used to simulate the mixture adsorption isotherm and selectivity. The simulated results are good agreement with the experiment data and the calculated results of IAST-DL model. The adsorption localization of C₄ hydrocarbons on ZSM-5 zeolite samples are simulated, and the simulated results show that the addition of a large amount of binder has a distinctly affection for the adsorption localization of C₄ hydrocarbons on ZSM-5 zeolites.4．The adsorption kinetic data of C₄ hydrocarbons on ZSM-5 zeolites are correlated in terms of the Fick diffusion model, and the diffusion coefficients of n-butane and butene-1 on ZSM-5 zeolites with different Si/Al ratios at 275, 288 and 300 K are obtained. In addition, the affection of temperature, pressure and Si/Al ratio to diffusion coefficients are discussed.更多还原