Predict Yields from a Kinetic Model of Catalytic Cracking Process at Any Temperature

Abstract

It has been observed that yields of gasoline and other petroleum fraction in a catalytic cracking process depends significantly upon the reaction temperature besides on other operating conditions. In this work, first the model was developed with the help of literature data with out considering the temperature effect. The important optimum parameters like relative rate constant (K ₁), rate of coke deactivation or decay constants (K_d ), order of reaction (m) etc. over suitable catalysts of cracking process were obtained using suitable numerical analysis techniques. On comparing the error based on the least square criteria, it has been noticed that the results from the first model show about 4% improvement in predicted error against literature results on cracking of normal Heptane [Corma, A., Wojciechowsky, B. W. ([1983] Corma, A. and Wojciechowsky, B.W. 1983. Recent work on the fundamentals of catalytic cracking. American Chemical Society Reprints, Div. Chem., 28(3): 861–874.  [Google Scholar]). Recent work on the fundamentals of catalytic cracking. American Chemical Society Reprints, Div. Chem. 28(3):861–874.] for fifteen data points. In the second step the software was modified to simulate the effect of reaction temperature by using two sets of laboratory data for the reaction of normal Hexadecane over ReY-Zeolite, a commercial cracking catalysts at two different reaction temperatures of 400 and 450°C respectively. Validation of modified software has been checked with the above system at 500°C and found that the predictions are quite close to experimental values. Such analytical model will be useful for finding optimum operating conditions to achieve maximum yields of potential products on cracking of a given feed without resource to conducting large number of experiments.     

An Orthogonal Method for Aromatization Reactions of Shenghua FCC Gasoline

Using a confined fluidized bed reactor and aromatization catalysts (LBO-A and LBO-16), the aromatization performance of Shenghua fluid catalytic cracking (FCC) gasoline has been studied in an orthogonal method. The experimental results reveal that the optimum reaction condition for the light oil yield was reaction temperature 420°C, WHSV 40 h^-1, mass ratio catalyst to oil 4 and 75% LBO-A and 25% LBO-16; the optimum reaction condition for aromatics amount in the light oil was reaction temperature 420°C, WHSV 30 h^-1, mass ratio catalyst to oil 5 and 65% LBO-A and 35% LBO-16, the olefin content is remarkably reduced from about 54.7% to 12.8% and 8.7% (by mass), respectively, at the same time the reaction mechanism of aromatization reaction is put forward based on the experimental result.     

碳四烯烃制丙烯和乙烯催化剂的研究

以超细SiO2为载体、水热稳定性好的高硅铝比ZRP-5分子筛为活性组分,通过挤条成型制成ZRP-5/SiO2催化剂,采用碱土金属氧化物对催化剂进行改性,考察催化剂的活性与表面酸性的关系。结果表明,B酸与催化剂的活性相关,经MgO,CaO,SrO改性后,催化剂的酸性和活性随Mg,Ca,Sr原子半径的增大而降低。采用MgO-CaO／ZRP-5／SiO2催化剂,在500 ℃、0.1 MPa、水与碳四原料质量比0.2、重时空速3 h-1的条件下连续反应50 d,反应产物组成稳定,碳四烯烃转化率大于65％,丙烯收率大于31％,乙烯收率大于6％,再生后催化剂可以恢复到新催化剂98％的水平。     

Etherification Performance of Transition Metals Modified β-Zeolite Catalyst

The etherification experiment for FCC light gasoline on transition metals modified Hβ zeolite was studied in a fixed-bed reactor. The effect of preparation condition of catalyst on the catalyst's activity, stability, and the effect of reaction temperature, methanol/tert-olefin molar ratio, and liquid hour space velocity on the etherification reaction were discussed. The experimental results showed that the different metals modified Hβ zeolite had different etherification performances. And the conversion of tertiary carbon-olefins of the molybdenum modified Hβ zeolite, which was loaded 3%, was higher 6.0% than the Hβ zeolite. The optimal reaction conditions were temperature 70-80°C, liquid hour space velocity 1.0 h^-1 and methanol/tert-olefin molar ratio 1.05. The modified Hβ zeolite catalysts possessed favorable prospect for its higher stability.     

重油催化裂解反应深度函数及裂解产品产率关联模型

提出了一个重油催化裂解反应深度函数,根据试验数据回归得到了其与反应温度、油气停留时间、剂油比和水油比等操作条件之间的关联式,并在此基础上建立了裂解产品产率与催化裂解反应深度函数和原料性质(氢碳原子比)之间的关联模型.模型的预测结果与试验结果吻合较好.     

A New Catalyst for the Non-hydrogenation Reduction of Olefins

In this article, the preparation and application of a nonhydrogenation-reducing olefin catalyst were studied. The carrier of this catalyst was synthesized by γ-Al₂O₃ and SiO₂. It was found that the optimum molar ratio was 1:1 and the more suitable synthetic temperature was 80°C. The catalyst consisted of transition element Ni, W loading on the carrier that was self-made. Meanwhile, the properties of the catalyst were determined by an x-ray diffraction pattern (XRD), N₂-adsorption, and an FT-IR spectrophotometer. In order to study the performance of the catalyst, it was dried and calcined, and then it was reacted with the feed gasoline on the small fixed vector. The results showed that the content of olefins in fluid catalytic cracking (FCC) gasoline had been reduced from 51.0% to 25.6% when the reaction temperature was 170°C, the space velocity was 1.5 h^-1, and the reaction pressure was 2.5 MPa. The experimental results showed that the method of the catalytic preparation was simple and convenient, the activity of the catalyst was very high, and the regeneration and stability were also very good. The olefin content was reduced by more than 20% in FCC gasoline; the original octane number was not changed. Therefore the quality of the gasoline would meet the new gasoline standard (GB). The catalyst had very high industrial application value.     

反应温度和剂油比对催化裂化反应的影响

选取各种不同孔径的分子筛催化剂如AIMCM-41、纳米双介孔分子筛(NBMAS)和微孔分子筛HZSM-5,以异丙苯和1,3,5-三异丙苯为模型反应物,采用脉冲法考察反应温度和剂油比对催化裂化反应的影响。实验结果表明,不同反应物的催化裂化反应采用不同的催化剂、反应温度和剂油比对裂解转化率和裂解产物的分布有不同的影响。异丙苯裂化反应中,在转化率增加的同时,小分子烯烃的选择性增加,其副产物(对-二异丙苯和间-二异丙苯)的选择性降低;在1,3,5-三异丙苯的裂解反应中,随着裂解程度的加深,小分子烯烃的选择性增加,中间产物(异丙苯和二异丙苯)的选择性降低。     

Hydrocracking of Tetralin over Mo-Ni/Usy Dual Functional Catalysts

Tetralin was chosen as a model compound to investigate the reaction networks and kinetics of hydrocracking of polynuclear aromatic hydrocarbons on modified zeolite Y based molybdenum-nickel dual functional catalysts using a continuous flow microreactor at 320-380°C, 8.5 MPa. According to the product distributions, the reaction network of hydrocracking of tetralin was proposed. The pseudo-first-order kinetics rate constants of each step in the network of hydrocracking of tetralin were evaluated by the nonlinear parameter estimation method. The results showed that reaction of hydrocracking of tetralin was a complicated parallel and serial reaction including hydrogenation, isomerization, and cracking (ring opening and dealkylation). The key steps of hydrocracking of tetralin, the conversion of double ring compounds and the yields of mono-ring compounds were affected by reaction temperature and acidity of supports on the catalysts.     

镍基催化剂催化正己烷异构化性能及热稳定性

采用干混和等体积浸渍法分别制备了NiB/Hβ、NiP/Hβ和Ni-HPWMo/Hβ3种烷烃异构化催化剂,并采用XRD、SEM、NH₃-TPD等手段对催化剂进行表征,考察了3种催化剂催化正己烷异构化的反应性能、热稳定性及650 ℃再生后催化异构化性能。结果表明：虽然3种催化剂均具有催化正己烷异构化的活性,但Ni-HPWMo/Hβ、NiB/Hβ的热稳定性较差,而且NiB/Hβ的催化裂解性能较强,导致裂解产物增多;在650 ℃下模拟工业条件再生后,Ni-HPWMo/Hβ和NiB/Hβ催化性能明显降低,NiP/Hβ依旧能保持稳定的催化异构化活性。通过对比3种镍基烷烃异构化催化剂的热稳定性及模拟再生性能,表明NiP/Hβ催化剂具有一定的工业应用前景。     

石脑油催化裂解生成甲烷的影响因素探析

对比分析了直馏石脑油热裂解和催化裂解过程中甲烷产率的差异及其根源,探索了工艺参数、催化剂活性和烃类分子结构对石脑油催化裂解反应中甲烷的产率和选择性的影响。结果表明：甲烷主要来自于石脑油的催化裂解反应,催化剂上的较强Br?nsted酸中心是甲烷生成的活性中心;链烷烃催化裂解更易于生成甲烷;反应温度和油剂接触时间是影响甲烷生成的关键因素,对此提出采用适宜反应温度和大剂油比,在保证原料必要的转化深度的同时,开发超短接触时间的反应技术以减少甲烷生成的技术构想。     

基于支持向量回归的重油催化裂化产物建模及优化

催化裂化反应的产物分布与反应原料组成及反应条件具有复杂的函数关系,以三种重油多个条件下的催化裂化实验结果为训练样本,利用支持向量回归方法建立汽油、柴油产物的产率模型。对于催化裂化回炼油,利用模型的泛化能力对不同操作条件下的汽油、柴油产率进行模拟仿真。以轻质油（汽油、柴油）产率最大为优化目标,利用粒子群算法寻找回炼油反应的最优操作条件。结果表明：模型对各反应条件下的实验结果有良好的拟合效果,模拟仿真的三维图可以直观显示各个反应条件对汽油、柴油产率的影响。优化得到的回炼油最佳反应条件为温度530 ℃,剂油质量比7.5,空速8 h-1。在最佳反应条件下,轻质油产率模拟值为42.3%,实验值为41.8%,相对误差为1.20%。     

三氧化钼催化合成季戊四醇四庚酸酯

通过焙烧法直接焙烧钼酸铵((NH₄)₆Mo₇O₂₄·4H₂O),制备了一种用于季戊四醇(PER)与正庚酸(HPA)酯化合成季戊四醇四庚酸酯(PETH)反应的三氧化钼(MoO₃)催化剂。采用X射线衍射(XRD)、N2吸附-脱附(BET)等手段对催化剂进行了表征。考察了焙烧温度、反应条件(温度、时间、原料配比、催化剂用量)等因素对催化剂性能的影响。结果表明：催化剂比表面积随着焙烧温度的升高而减小,催化剂催化活性也随之减弱;在焙烧温度400、500 ℃下制得的MoO₃为晶面(021)、(110)、(040)同时择优取向α-MoO₃,在焙烧温度600 ℃下制得的MoO₃为(020)、(021)、(110) 晶面同时择优取向α-MoO₃;在400、500 ℃下焙烧制得的(021)、(110)、(040) 晶面同时择优取向α-MoO₃催化剂的催化活性最优,择优取向晶面(021)和/或(110)更利于PER与HPA酯化合成PETH反应。在适宜的反应工艺条件(T=200℃,t=4 h, n(HPA)/n(PER)=4.2, n(MoO₃)/n(PER)=0.004)下,PER转化率达到100%,PETH的选择性达到100%。     

The Use of ANN and the Mathematical Model for Prediction of the Main Product Yields in the Thermal Cracking of Naphtha

Thermal cracking of naphtha has such numerous reaction routes that the detailed reaction mechanism has not yet been determined. In this regard, a model of artificial neural networks (ANNs), using back propagation (BP), is developed for modeling thermal cracking of naphtha. The optimum structure of the neural network was determined by a trial-and-error method. Different structures were tried with several neurons in the hidden layer. The model investigates the influence of the coil outlet temperature, the pressure of the reactor, the steam ratio (H2O/naphtha), and the residence time on the pyrolysis product yields. A good agreement was found between model results and experimental data. A comparison between the results of the mathematical model and the designed ANN was also conducted and the relative absolute error was calculated. Performance of the ANN model was better than the mathematical model.     

加拿大合成原油减压馏分油催化裂化反应性能的研究

以大港石化公司提供的工业平衡催化剂LBO-16为催化剂,在小型固定流化床实验装置上考察了反应温度、剂油比和重时空速对加拿大合成原油（SCO）减压馏分油（VGO）、混合原油（SCO：大港原油为3：7）减压馏分油及大港原油减压瓦斯油的催化裂化产物产率和分布的影响。研究结果表明,反应条件对三种减压馏分油的催化裂化产物变化规律的影响是一致的,反应条件对大港减压馏分油的影响较大。在最优的反应条件下,加拿大合成原油减压馏分油的轻质油收率为64．5％,混合减压馏分油的轻质油收率为66％左右,加拿大合成原油减压馏分油和大港减压瓦斯油相比,有较低的焦炭和液化石油气产率以及较高的柴油产率。     

分子筛类型对正戊烷催化裂解反应性能的影响

为了解决石脑油中正戊烷难以高效催化裂解为低碳烯烃的问题,先采用Aspen Plus模拟软件对正戊烷的催化裂解反应进行热力学平衡分析,然后考察分子筛类型对正戊烷催化裂解的低碳烯烃收率和选择性的影响规律。对正戊烷的催化裂解反应进行热力学分析的结果表明,当反应温度高于650 ℃时,丙烯和乙烯的质量比m(C₃H₆)/m(C₂H₄)<1,且低碳烯烃(C₂H₄+C₃H₆+C₄H₈)的收率开始增速缓慢。因此,综合考虑m(C₃H₆)/m(C₂H₄)和低碳烯烃收率,选择在反应温度650 ℃下考察正戊烷在不同类型分子筛上的催化裂解反应性能。结果表明：在MTT分子筛上催化裂解的低碳烯烃选择性较高,在温度为650 ℃、压力为0.1MPa、MHSV为540 h^-1的反应条件下,正戊烷在MTT分子筛上催化裂解的低碳烯烃(C₂H₄+C₃H₆+C₄H₈)选择性为55.21%。通过对催化裂解过程的裂解和氢转移反应的分析,表明小孔径的MTT分子筛能够抑制双分子反应,包括双分子裂解反应和双分子氢转移反应,从而提高低碳烯烃的选择性。     

正丁烷催化裂解制乙烯和丙烯的研究

在固定床微型反应器装置上,对正丁烷在5种不同催化裂化催化剂上的裂解反应过程进行了考察。结果表明,其中ZRP-1催化剂的乙烯和丙烯收率最高。进一步考察了在ZRP-1催化剂上不同的反应条件对于正丁烷转化率和乙烯与丙烯的收率及选择性的影响。结果表明,正丁烷催化裂解的最佳工艺条件为:反应温度640℃,催化剂装量0.5g,气体流量0.03L/min。在该条件下乙烯和丙烯的收率分别为19.6%和17.8%。     

PYROLYSIS OF BLACK LIQUOR BY USING SOME BASIC CATALYSTS

Catalytic pyrolysis for the production of liquids and gases from acidic precipated of black liquor was carried out by using CaO and CuCO₃,Cu(OH)₂ catalysts. This process has been studied in the temperature range from 463 to 570 K. Pyrolysis of black liquor in the temperature range 463-570 K gave yields which increased from 25·9 to 29·0 % as the catalyst percentages was increased from 5 to 20 % for CaO. Under the same conditions, the yields of pyrolysis increased from25·5 to 28·3 for CuCO₃.Cu(OH)₂.     

Y和Beta分子筛对环烷基直馏柴油加氢裂化性能的影响

分别以改性Y分子筛、H-Beta分子筛及改性Y/H-Beta复配分子筛为酸性组分制备载体,然后采用等体积浸渍法制备Ni-Mo型加氢裂化催化剂。通过X射线衍射、N₂吸附-脱附、NH₃-程序升温脱附、吡啶吸附红外光谱、H₂-程序升温还原等方法对催化剂进行分析表征,结果表明：与采用改性Y分子筛、H-Beta分子筛制备的催化剂相比,采用改性Y/H-Beta复配分子筛制备的催化剂有较适宜的酸量和酸强度,活性金属分散均匀,催化剂的裂化和加氢功能匹配合理。以环烷基直馏柴油为原料,在较高的反应温度条件下,3种催化剂中改性复配分子筛催化剂明显抑制了二次裂化反应,在较高转化率条件下,其加氢裂化产物总液体收率最高,轻石脑油收率最低,重石脑油收率最高,重石脑油芳烃潜含量和柴油十六烷值均较高。     

MODELING FOR PRODUCT DISTRIBUTION IN THERMAL CONVERSION OF HEAVY OIL

A laboratory scale microstatic reactor was developed for heavy oil thermal conversion. This apparatus can be temperature programmed quickly and smoothly in the range of 400-500°C. The product distribution was determined with Soxhlet apparatus and liquid chromatography. It is assumed that both cracking and condensation reactions are first order reactions and no secondary reaction occurred for the product. A twelve lumped reaction model for product distribution in thermal conversion of heavy stock was developed. The regression coefficient R and F test indicate that the model was fit well to the experimental data at low thermal conversion. Therefore, the model can predict the cracking and condensation reactions of heavy stock occurring in the inner tube of a coking heater.     

The Use of ANN and the Mathematical Model for Prediction of the Main Product Yields in the Thermal Cracking of Naphtha

Abstract

Thermal cracking of naphtha has such numerous reaction routes that the detailed reaction mechanism has not yet been determined. In this regard, a model of artificial neural networks (ANNs), using back propagation (BP), is developed for modeling thermal cracking of naphtha. The optimum structure of the neural network was determined by a trial-and-error method. Different structures were tried with several neurons in the hidden layer. The model investigates the influence of the coil outlet temperature, the pressure of the reactor, the steam ratio (H2O/naphtha), and the residence time on the pyrolysis product yields. A good agreement was found between model results and experimental data. A comparison between the results of the mathematical model and the designed ANN was also conducted and the relative absolute error was calculated. Performance of the ANN model was better than the mathematical model.