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Development of a Kinetic Model for Thermal Cracking of Aromatic Hydrocarbon Feeds

Rezaei Babadi, Ebrahim | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55274 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Khorasheh, Farhad; Ivakpour, Javad
  7. Abstract:
  8. Most refineries are looking for a process in order to remove heavy compounds and convert them into lighter, more valuable materials. Among the various remaining upgrade processes, non-catalytic heating processes are very attractive and have gotten a wider scope worldwide because the feed used for the upgrade process is high in metal and sulfur, which causes the catalyst surface to become toxic and inactive. Due to that, the thermal cracking process is more suitable for such feeds than the catalytic cracking process. Due to the reduction of sweet crude oil resources and the heavier refinery feeds and increase in amount of global fuel needs, refineries must process a larger share of feed in heavy-duty quality improvement units using appropriate methods and optimize the conditions of refining processes. Therefore, simulation, design and optimization of these processes can help to implement them in refineries.In the present study, the vacuum residue of one of the country's refineries was first separated into Pitch, Aromatic-maltene and Saturation-maltene components by repeating the deasphalten process with ethyl acetate and isopropyl acetate solvents. 32%wt of pitch part and. 51.8%wt of Aromatic-maltene part was separated by deasphalten process using ethyl acetate as the solvent.20 thermal cracking tests in the temperature range of (400-500) ° C, time period of (5-125) minutes and the temperature increase rate in the range (1-5) ° C per minute were programmed by Response Surface method and Central Composite Design procedure in Design Expert software. Then, the analysis of variance test was obtained for each product and the effect of each of the factors of reaction temperature, reaction time and temperature increase rate on product yield was investigated. Finally, a 6-lamp kinetic model for the reactions can be suggested. The lamps of this model include: Pitch, Aromatic-maltene and Saturation-maltene as feed lamps and also include Distillate, Gas and Coke lamps as product lamps. In this modeling, having the gas flow rates during the process and also having the final products, the reaction rate constants as well as the concentration profile of the distillation products and coke during the reaction can be drawn.
  9. Keywords:
  10. Solvent Deasphalting ; Vacuum Residue ; Delayed Coking ; Kinetic Model ; Aromatic Compounds ; Thermal Break

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