CPD NR3266 Conceptual Process Design
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CPD NR3266 Conceptual Process Design Process Systems Engineering DelftChemTech - Faculty of Applied Sciences Delft University of Technology Subject Downstream de-bottlenecking of the Naphta Reformer at the oil refinery of PetroPlus, Antwerp Authors Telephone T. Chang 06-41377486 J.M. Huijser 070-3904358 N. Maassen 0182-630774 A. de Winter 015-2628991 Keywords Benzene, Refinery, Reformer, Splitter, Hydrogenation Nickel catalyst, Cyclohexane, Aromatics, Gasoline, RON Assignment issued : 09/27/2001 Report issued : 12/19/2001 Appraisal : 01/14/2002 Preface This report has been written by four students of the Delft University of Technology (DUT) during the months of October – December 2001. It has been written by order of PetroPlus and of DUT, within the framework of 4th year conceptual design project of the study Chemical Engineering. The assignment was, to come up with a solution to decrease the benzene content in the reformate produced by the PetroPlus refinery in Antwerp, from 1.5 vol% to 1 vol% or lower. In Chapter 2 several options were suggested. The solution with best prospects is splitting and hydrogenation of the benzene. Therefore this option has been examined in detail. We would like to express our acknowledgements to: Dr. Raimond Bonné Dr. Ir. Albert Gerritsen Ir. Arjan van der Griendt Ir. Patrick Ham MTD Ir. Bram Hoffer Prof. Freek Kapteijn Dr. Martin Lok Dr. Ir. Michiel Makkee Prof. Jacob Moulijn Dhr. D. Ott Prof. Tapio Salmi Drs. Peter Scherp (Procatalyse) Ir. Pieter Swinkels Dhr. M.C. Valentijn Delft, 19 December 2001, Lilian Chang Annemarie Huijser Noortje Maassen Annemieke de Winter Downstream de-bottlenecking of the Naphta Reformer at the oil refinery of PetroPlus, Antwerp i Summary The focus of this project is to upgrade the reformate stream produced by our principal, PetroPlus refinery in Antwerp. Petroplus is one of the leading midstream oil and storage companies in Europe, founded in 1993. Reformate is used as a blending material for gasoline. Currently this reformate stream contains a 1.5 vol% of benzene. As a result of recent changes in European legislation, PetroPlus is forced towards the production of reformate containing at most 1 vol% benzene. Additional specifications are that the RON must be kept at 99.5 and that the throughput of reformate has to be maximized by changing the 50/50 LDN/HDN ratio back to 30/70. So the objective is to design a process, which offers a solution to the criteria stated by the principal. The present production rate of reformate is 290 kton/a with benzene content of 1.5 vol%. The market price of this reformate is US$ 215 /ton. To satisfy the objective, benzene is splitted from the reformate stream and hydrogenated. The process is called the Debenzenizer. The design of the Debenzenizer results in a production rate of reformate of 375 kton/a with benzene content of 0.59 vol%. The market price of this reformate is estimated at US$ 220 /ton. The designed process resembles to the IFP BenfreeTM process, but there are also differences. Possibly, license costs have to be paid for the IFP BenfreeTM process. In ideal case, when shutdowns are neglected, the on-stream factor is one, because the process is carried out continuously. With the designed units, a positive cash flow after tax of US$ 0.85 million is realized, compared to the present situation. The related Pay Out Time after tax is 3 years, with a DCFROR of 37.0 %. These economic criteria are based on a price difference between the present reformate and the reformate produced when using the Debenzenizer of US$ 5 /ton. The total investment for the new installation is US$ 3.13 million. The economic plant life is 27 years. The price of the raw materials influences the economic results strongly and the price of products also quite influences the economics. The prices of utilities and equipment have only a slight influence. The designed process fulfills all specifications that have been given by the principal. The benzene content of the reformate stream is 0.59 vol%, the naphta split ratio is 30/70 and the RON of the product is 99.5. Two weaknesses of the design are the exothermic character of the hydrogenation of benzene and the temperature of the top of the split column. The first weakness is dealt with in the design. As far as the second weakness is concerned, it is recommended to review the designed height of and the pressure in the split column. Hydrogenation of benzene to cyclohexane leads to a decrease of the RON. It is recommended to optimize the design so that the final benzene concentration is 1 vol% and the RON is 99.5. Downstream de-bottlenecking of the Naphta Reformer at the oil refinery of PetroPlus, Antwerp ii Finger print of the Debenzenizer Debenzenized Reformate 49.4 t/h Benzene-rich (1.00 t/t) 49.4 t/h Reformate (1.02 t/t) Hp Vapor outlet 2.7 t/h (0.06 t/t) Debenzenizer Fresh H2 FG LDN 0.8 t/h 3.2 t/h to R201 (0.02 t/t) (0.06 t/t) Fuel gas 0.8 t/h (0.02 t/t) Downstream de-bottlenecking of the Naphta Reformer at the oil refinery of PetroPlus, Antwerp iii Table of contents Preface ................................................................................................................................... i Summary ............................................................................................................................... ii Finger print of the Debenzenizer....................................................................................... iii List of Appendices ............................................................................................................. vii Chapter 1 Introduction ................................................................................................... 1 Chapter 2 Process options & Selection ....................................................................... 4 2.1 Process options ....................................................................................................................... 4 2.2 Selected process option .......................................................................................................... 6 2.2.1 Mode of operation ........................................................................................................... 7 2.2.2 Block scheme................................................................................................................... 8 Chapter 3 Basis of design ........................................................................................... 10 3.1 Description of the design ..................................................................................................... 10 3.2 Process definition ................................................................................................................. 10 3.2.1 Selection of Process Concept ........................................................................................ 10 3.2.2 Stoichiometry ................................................................................................................ 10 3.2.3 Kinetics and catalyst ...................................................................................................... 11 3.3 Block schemes ...................................................................................................................... 13 3.4 Thermodynamic properties ................................................................................................ 14 3.4.1 Thermodynamic data of the hydrogenation reaction of benzene ................................... 14 3.4.2 Selection of Thermodynamic models for the simulation of the Debenzenizer .............. 14 3.5 Pure component properties ................................................................................................ 15 3.6 Basic Assumptions ............................................................................................................... 15 3.6.1 Plant Capacity ................................................................................................................ 15 3.6.2 Location ......................................................................................................................... 16 3.6.3 Battery Limit ................................................................................................................. 16 3.6.4 In– and outgoing streams ............................................................................................... 16 3.7 Economic margin ................................................................................................................. 18 Chapter 4 Thermodynamic properties ....................................................................... 19 Downstream de-bottlenecking of the Naphta Reformer at the oil refinery of PetroPlus, Antwerp iv 4.1 Thermodynamic models ...................................................................................................... 19 4.1.1 Splitter ........................................................................................................................... 19 4.1.2. Hydrogenator ................................................................................................................. 19 4.1.3 Pressure changers .......................................................................................................... 20 4.1.4 Heat exchangers............................................................................................................. 21 4.1.5 Separators .....................................................................................................................