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Pdf 877.25 K E. S. Moosavi et al. / Journal of Chemical and Petroleum Engineering, 52 (1), June 2018 / 23-33 23 Deasphalting of Olefin Pyrolysis Fuel Oil by Combination of Chemical–Physical Methods E. S. Moosavi1, M. Gharibi*2, R. Karimzadeh*3, B. Asbaghi2, 2 3 3 S. S. Shahabi , S. Aalizad and M. Zare 1. Chemical and Materials Engineering Department, Buein Zahra Technical University, Buein Zahra, Qazvin, Iran. 2. National Petrochemical Company, Petrochemical Research and Technology Company, P.O. Box 1435884711, Tehran, Iran. 3. Chemical Engineering Faculty, Tarbiat Modares University, P.O. Box 14155-4838, Tehran, Iran. (Received 14 August 2017, Accepted 26 February 2018) [DOI: 10.22059/jchpe.2018.239677.1207] Abstract Keywords Fuel Oil (PFO) thermal cracking of two PFO samples on liquid, solid This work investigated the effect of different conditions of Pyrolysis Asphaltene; Naphthalene; and gas product yields and asphaltene removal efficiency in a newly- Product yield; designed experimental setup. There is no need to use a catalyst, simple Pyrolysis fuel oil (PFO); operating system and experiment conditions. The ability to use wa Thermal cracking. ter as a cheap carrier gas and high asphaltene extraction efficiency- paredwithout in thevarious use of operating solvents conditionsare outstanding and the benefits optimum of this experimental method in upgrading PFO. The yields of liquid, solid and gas products were com- ing condition of PFO in terms of liquid yield and asphaltene removal in conditions were obtained. The results revealed the best thermal crack this setup for samples. The optimum conditions were 390 and 380°C rate.for the In reactorthese circumstances temperature aboutof PFO-1 70 and 53PFO-2, wt% respectively; of the liquid 150°Cprod- uct,for the 25 temperaturewt% of the solid of carrier products, gas and and 100 5 wt% ml/min of the for gascarrier product gas flow are generated and the asphaltene separation was reached about 95 and 96.5%. 1. Introduction cts so that their upgrading processes have gained worldwide interest which requires the use of he residues of production lines in petro- units to prevent high yields of coke and more chemical industry, such as pyrolysis fuel oil beneficial yields of distillate products in order to T in olefin plant, are the least valuable produ- convert oil residue into more desirable products. 1 Introduction A mixture of high boiling aromatic hydrocarbons, produced as a by-product during pyrolysis of oil * Corresponding Authors. fractions is a dark brown to black colored viscous liquid with pour point approximately 15 °C and a | Email: [email protected] (M. Gharibi) Tel.: +98 21 44787517; fax: +98 21 44787501 distinctive mothball-like odor classified as a haz- | Email: [email protected] (R. Karimzadeh) ardous substance with carcinogenic components Tel.: +98 21 82883315; fax: +98 21 88006544 24 E. S. Moosavi et al. / Journal of Chemical and Petroleum Engineering, 52 (1), June 2018 / 23-33 according to EC directives and used as a raw ma- produce deasphalted liquid product, as a light terial for manufacturing carbon black or burned feedstock. as industrial fuels. The pyrolysis fuel oil (PFO) Solvent deasphalting (SDA), as another separa- feedstock contains about 30 to 35 (w/w %) of tion process in which the residue is separated by asphaltenes in matrix solution which consists the molecular weight (density) instead of boiling highest molecular weight and aromatic hetero point, would require a high volume of solvent compounds with aliphatic substitutions, the ma- which would allow us to deduce the fact that this jority of impurities and hetero elements, and low process cannot be regarded as a beneficial one, hydrogen to carbon ratios. Furthermore, it is the from an economic point of view [16]. Asphaltenes most complicated fraction which contains more are not crystallized and cannot be divided into than thousands different molecules [1-7]. individual components or narrow fractions. In the last few years, characterization of asphal- Thermal cracking of heavy oils, especially the re- tene precipitation has been investigated [8-10]. sidual feedstock, and investigation of the yields While asphaltenes act as coke precursors which and properties of the product of this process in would lead to catalyst deactivation, the compli- different conditions and severities have been the cated macromolecular structure of asphaltene point of focus and interest in most of the previ- strongly affects upgrading and refining opera- ously conducted studies [9, 10, 17-20]. Neverthe- tions and determines the quality and processing less, due to the high content of asphaltenes and effect of PFO to a certain degree. Problems asso- aromatic compounds in the range of naphthalene ciated with asphaltene precipitation and deposi- in PFO, it is not possible to upgrade this new ma- tion have been widely reported in the petroleum terial (i.e. PFO) in a single step by the currently production and processing industry [11-14]. En- available methods (such as Eruka process). hanced oil recovery techniques have also led to Therefore, the primary process should include some asphaltene problems. These these com- the elimination of these troublesome compounds. pounds could be prone to condensation and cok- However, the use of a new system is necessary in ing during processing and would deactivate cata- order to resolve the problem of naphthalenic lysts. compounds which could eclipse and stop the op- In recent years, several technologies have been eration because of their deposition along the developed for residual oil upgrading and several path. researchers have been trying to improve the pro- The main concern and focal point of this research cessing technologies of heavy fuel oils by reduc- would be the study of PFO upgrading, olefin plant ing asphaltene because it has been proved that by-product, and using a newly designed setup in one of the most important problems related to order to remove asphaltene from two PFO sam- governing processes of these technologies would ples and, in the meantime, naphthalenes removal be high content of resins and asphaltenes. from one of the PFO samples to the next upgrad- Thermal cracking processes which could be used ing processes and obtain valuable compounds. in the refining industry, including delayed coking, The innovative aspect of the newly designed ex- fluid coking, flexi-coking, visbreaking, and Eureka perimental setup is the use of a special condenser process, not only do facilitate the operation to for the separation of aromatic compounds such as have a condition of low pressure and high to naphthalene because these materials immediately moderate working temperatures with no demand result in condenser congestion during exiting the for expensive catalysts, but also provide us with a reactor. This section has not been predicted in simple robust control operation [15]. previous studies. Therefore, this setup can also be used to refine the compounds containing naph- It could be possible to remove the asphaltene thalene. fraction, as the precursors of coke formation, from heavy and residual feedstock by Eureka While generating the maximum amount of liquid process which is a commercially proven thermal product containing the minimum amount of as- cracking process that produces deasphalted liq- phaltene has been another objective of this study, uid product, as a light feedstock and aromatic pe- the yields of liquid, solid and gas products have troleum pitch, from vacuum residues in order to been compared in various operating conditions and an optimum experimental condition is ob- E. S. Moosavi et al. / Journal of Chemical and Petroleum Engineering, 52 (1), June 2018 / 23-33 25 according to EC directives and used as a raw ma- produce deasphalted liquid product, as a light tained under different experimental conditions, specified inside temperature in a heating mantle terial for manufacturing carbon black or burned feedstock. asphaltenes are precipitated in a rejected fuel oil equipped with a temperature controller and insu- as industrial fuels. The pyrolysis fuel oil (PFO) with light alkane precipitants (i.e., n-pentane, and lated with glass wool jacket, was used as a ther- Solvent deasphalting (SDA), as another separa- feedstock contains about 30 to 35 (w/w %) of n-heptane) and characterized using some com- mal cracking reactor. In each test, the reactor was tion process in which the residue is separated by asphaltenes in matrix solution which consists the mon analytical techniques. loaded with 100 g of PFO. Pre-heated carrier gas molecular weight (density) instead of boiling highest molecular weight and aromatic hetero (N or Steam) stream was injected at a constant point, would require a high volume of solvent Due to the variety of feed in petrochemical plants 2 compounds with aliphatic substitutions, the ma- flow rate into the reactor to evacuate the prod- which would allow us to deduce the fact that this such as naphtha, gaseous feeds: propane, ethane, jority of impurities and hetero elements, and low ucts immediately after formation and to mix the process cannot be regarded as a beneficial one, etc., two olefin plants were selected from each hydrogen to carbon ratios. Furthermore, it is the feed. Two design approaches were applied for from an economic point of view [16]. Asphaltenes category. Having prepared the two samples of most complicated fraction which contains more two different PFO samples upgrading process. In are not crystallized and cannot be divided into PFOs from different Iranian
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