1. Sheme 1. Scheme of units for pyrolitic oil fractionation: B1-Feed heater; B2-Separation column (separation of components in distillate: comp. 8= 90% and comp. 9= 15% ); B3-Indane/Inden Column; B4 – Naphthalene column; B5, B10-B13, B20 – Heat exchangers; B7 and B9 –pressure reduction Design of industrial plant for naphthalene separation from pyrolysis fuel oil: Calculation of energy consumption and operating expenditures Zoran Popović 1, Ivan Soucek 2, Stansislav Bruna 2, Veljko Unković 3, Dejan Skala 4 University of Belgrade, 1 Institut for Chemistry, Technology and Metallurgy, and 4 Faculty of Technology and Metallurgy, Belgrad, Serbia; 3 Institut of Chemical Technology, Praha, Czech Republic 3 Transnafta, Pancevo, Serbia 2 Design of industrial process of petrochemical-based naphthalene isolation from pyrolysis fuel oil (PFO), which is residual output stream in the pyrolysis of naphtha to olefins is presented in this study. Naphthalene could be separated from PFO by distillation similar to the recovery of naphthalene from coal-tar (distillation and crystallization ). The following compounds were used for presenting PFO used for process design: S TYRENE ; I NDAN, I NDENE, 1,2- DIMETHYL -3- ETHYLBENZENE, C IS -2- PHENYLBUTENE -2, 1- METHYLINDENE, 2- METHYLINDENE, N APHTHALENE, 4- ISOBUTYLSTYRENE, 1- METHYL - NAPHTHALENE, 2- METHYL - NAPHTHALENE, D IPHENYL, 2,6- DIMETHYL - NAPHTHALENE, F LUORENE AND A NTHRACENE. PFO contains many hydrocarbons in the boiling range from 160-280 o C (TBP) and almost 25-30 wt% of naphthalene which might be isolated with various yield and purity grade. Two constraints were used: the yield of isolated naphthalene must be at least 85% on the basis of initial amount of naphthalene present in PFO with purity higher then 98.5%. The goal of this study was to show in which extent defined yield and naphthalene purity influences the energy consumption for napthalene isolation from PFO (feed 32 kt/year; 8000 h/year) and operating expenditures (OPEX) as a function of yield and purity of naphthalene isolation. The following main equipments are included in design of Naphthalene Plant (Scheme 1&2): fired heater, three distillation columns which contain corresponding reboilers and condensers and several heat exchangers. Among distillation column, the first one was the most important because it determine the final yield of naphthalene isolation and thus influence how much is energy consumed in whole process. Two different arangement was analyzed: the first column as simple the flash column (Scheme 1) or the second arrangement where the first column is distillation column which include several plates (10) and corresponding reflux ratio.The second column in both scheme is used for separation of lighter compounds (more volatile from naphthalene) from crude naphthalene (C10H8 plus heavier compounds). Third column is used for final purification of naphthalene from less volatile compounds. The usual methodology, which is specifically developed for refining processes, was used for calculating of material flows and energy consumption, as well as for preliminary designing size of the main equipment. The real parameters for each mixture were calculated by using of ideal and real behavior characteristics of complex mixture. Calculation for real mixture was based on RK- Soave and SRK Equations of state. Preliminary plant design of naphthalene isolation was used for calculation of all individual items of operating expenditures based on annual consumption of feedstock and energy (cooling water, HP steam, electricity). Conclusion: Performed calculation indicated that operating expenditures (OPEX) is very sensitive to the yield and purity of naphthalene isolation. Although isolation of naphthalene according to the Scheme 2 is related to a higher amount of investmant cost as well as to the energy consumption it might be covered by higher production of naphthalene thus giving acceptable rate of investmant..