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With the aim of investigating the solutions of ethane shortage in a commercial ethylene plant, addition of propane as supplementary feedstock and increasing steam to hydrocarbon ratio were proposed as possible strategies. These strategies were proposed to compensate for the ethane shortage in the thermal cracking unit of the commercial plant. Run length, ethylene yield, and propylene yield were considered as the determining factors to appraise the strategies. The major contribution of present work would be the investigation of effect of feed shift on the run length of the steam cracker. Regarding this, five different cases were investigated in real plant condition. To include all the aspects of process, a mathematical model with reasonable assumptions was developed and then validated against the real plant data. Based on the obtained results, increasing propane concentration leads to increase in propylene yield and decrease in ethylene yield. Besides, run length of process was obtained to be longer in the cases with higher propane content in the feed stream.

Due to importance of acetylene removal from ethylene rich stream in polymerization units in order to prevent formation of highly explosive compounds, presenting any strategies improving the process efficiency has attracted researchers and industries interests. Proposing novel configurations in the reaction-regeneration cycles with lower energy consumption and enhanced catalyst lifetime leading to profits for the polymerization units is of a great interest. In this regard, a new configuration for the tail-end acetylene hydrogenation reactor of a commercial olefin plant was proposed in the present study. Based on the proposed configuration, a new protocol is applied to the process for utilizing total capacity of active catalysts in each fixed bed. A mathematical model based on component and energy balance was developed and validated to evaluate the operability of the proposed configuration. Operation of different runs in the new protocol was compared with the conventional configuration. The obtained results revealed that the new configuration is managed to decrease the volume of the regenerated catalyst in a 4-year period of operation. A 33.3% decrease in the volume of the regenerated catalyst was observed. Such an achievement was obtained without reducing acetylene conversion and ethylene yield.

The aim of present study is to develop a mathematical model to predict water and salt separation efficiencies in an industrial two stages crude oil desalting process. The considered process consists of mixing valve and electrostatic drums connected in series. The desalting plant is modeled based on the population balance method considering water droplet breakage and coalescence terms to predict droplet size distribution. The class method as a common mathematical technique is selected to solve population balance equation. The accuracy of the developed mathematical model and considered assumption is evaluated using taken data from an industrial desalting plant. Then, the effect of mixing valve pressure drop, flow rate of fresh water and strength of electric field is studied on the desalting and dehydration efficiencies. The simulation result shows that increasing flow rate of fresh water from 3% to 6% decreases salt content in the treated crude oil from 2.06 to 0.71 PTB.

In the present study, an accomplished reaction network is developed for commercial conversion of heavy reformates to more valuable xylenes. The proposed kinetic model is based on 18 pseudo-components and 39 related reactions in which 7 different types of reactions are included. Thermodynamic principles are also applied to predict the reversibility of the reactions. To estimate the reaction rate constants, the absolute deviation between the model results and observed data are minimized applying differential evolution (DE) optimization method. To prove the accuracy of the proposed model, simulation results are compared with the plant data and an acceptable agreement is achieved. Then, the effect of operating conditions on the reactor performance is verified. The results of this work show that increasing the inlet temperature and molar flow rate up to certain values would improve the xylenes production.

The already numerous industrial applications of alcohols is continuously growing to even higher significance. Accurate estimations of the physical properties of various alcohols within wide ranges of pressures and temperatures are necessary in the design and optimum operation of such processes. In this study, high-pressure liquid densities of the first six members of the normal alkanol family were predicted as a function of temperature and pressure. This was done using two different approaches: The computer method of support vector machine (SVM) and the thermodynamic model of Cubic Plus Association Equation of State (CPA EoS). A total of 2979 experimental data on alcohol density, also covering high pressure and high temperature conditions, were obtained from literature. The results of the calculations show that the value of AARD% for all of the 2979 data was 0.06% for the SVM computer model and 1.36% for the thermodynamic CPA model.