University of Pennsylvania ScholarlyCommons Department of Chemical & Biomolecular Senior Design Reports (CBE) Engineering 4-14-2009 TOLUENE METHYLATION TO PARA-XYLENE Thomas Dursch University of Pennsylvania Ramy Khalil University of Pennsylvania Annika Khine University of Pennsylvania Francisca Mutahi University of Pennsylvania Follow this and additional works at: https://repository.upenn.edu/cbe_sdr Part of the Chemical Engineering Commons Dursch, Thomas; Khalil, Ramy; Khine, Annika; and Mutahi, Francisca, "TOLUENE METHYLATION TO PARA- XYLENE" (2009). Senior Design Reports (CBE). 7. https://repository.upenn.edu/cbe_sdr/7 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/cbe_sdr/7 For more information, please contact [email protected]. TOLUENE METHYLATION TO PARA-XYLENE Abstract This design project explores the economic viability of a novel technology for the production of para-xylene via the methylation of toluene. Current production processes yield an unsatisfactory equilibrium mixture of xylene isomers only 23% pure in para-xylene. This low yield of para-xylene necessitates the use of prohibitively expensive separation processes such as the absorptive separation process, Parex, licensed at a whopping $57 million – not including utilities. A new process patented by Breen et al. makes use of an oxide-modified ZSM-5 catalyst and short catalyst contact times to achieve a 99.9% para-xylene selectivity. This design allows for the production of 99.9% pure para-xylene by use of conventional decantation and distillation. This project investigates the economic and environmental feasibility of converting 400 million lb/yr of toluene to para-xylene. The methylation reactor is designed according to patent specifications ot reproduce operating conditions that yield a 99.9% para-xylene selectivity and a 100% single-pass methanol conversion. Conserving resources is prioritized through extensive recycling of reactants and through introduction of an intricate heat exchanger network that capitalizes upon the high exothermic nature of the reaction. The Total Capital Investment for the process is $63,170,900 with a projected Net Present Value in 15 years of $60,468,500 and an Investor’s Rate of Return of 28.80%. In light of the economic profitability of the process and the projected increase in demand for para-xylene, it is recommended that the design be considered for further implementation. Disciplines Chemical Engineering This article is available at ScholarlyCommons: https://repository.upenn.edu/cbe_sdr/7 TOLUENE METHYLATION TO PARA-XYLENE Senior Design Project Thomas Dursch Ramy Khalil Annika Khine Francisca Mutahi Submitted to Professor Leonard Fabiano Mr. Bruce Vrana April 14, 2009 Department of Chemical Engineering School of Engineering and Applied Science University of Pennsylvania April 14, 2009 Department of Chemical Engineering School of Engineering and Applied Sciences University of Pennsylvania 220 S. 34th Street Philadelphia, PA 19104 Dear Professor Fabiano and Mr. Vrana, This report describes the design of a full-scale plant that produces para-xylene from methylation of toluene using new reaction technologies outlined in U.S. Patent 7,321,072 B2. In this highly exothermic reaction, toluene converts to xylene when mixed with methanol under high temperatures. The new technology introduced in this patent allows both for 100% converstion of methanol and 99.9% selectivity of para-xylene isomer formation. This technology is a significant improvement over current methods of para-xylene formation that involve far lower selectivity towards para-xylene formation and demand complex, downstream separation technologies such as crystallization and membrane separation. It is less capital intensive, more environmentally sound, more energy efficient, and results in less equipment maintenance. This design converts 400MM pounds per year of toluene purchased at $2.50 per gallon from an adjacent production facility. Likewise, methanol is available on-site for $1.00 per gallon. This plant currently produces 447,132,011 pounds of product 99.9% pure in para-xylene. This can currently be sold at $0.60 per pound. The plant requires a total capital investment of $63,170,900 and has a net present value of $60,468,500. This design provides an investor’s rate of return of 28.8%. Our design team strongly recommends that this design be considered for implementation following further investigation into the scale-up of the reactor technology. Sincerely, Thomas Dursch Ramy Khalil Annika Khine Francisca Mutahi TABLE OF CONTENTS ABSTRACT ........................................................................................................................................... 1 INTRODUCTION ................................................................................................................................. 2 Para-xylene Overview and Market Analysis ....................................................................................... 2 Industrial Value of Para-Xylene During PET Formation ..................................................................... 4 Existing Methods for Production ......................................................................................................... 4 A New Method for Production ............................................................................................................ 6 Effect of Catalyst Contact Time on Para-xylene Selectivity ............................................................... 7 PROCESS FLOW DIAGRAMS AND MATERIAL BALANCES ...................................................... 9 Process Overview ............................................................................................................................... 9 Process Flow Diagrams ..................................................................................................................... 11 Process Section 100: Methylation reaction ........................................................................................ 18 Introduction ................................................................................................................................. 18 Reactor Feed ................................................................................................................................ 19 Reactor Temperature Control ....................................................................................................... 19 Reactor Geometry ........................................................................................................................ 20 Additional Reactor Considerations ............................................................................................... 21 Process Section 200: Heat Exchanger Network.................................................................................. 23 Introduction ................................................................................................................................. 23 Heat Exchanger Network.............................................................................................................. 23 Economic Justification of Heat Integration ................................................................................... 24 Process Section 300: Separation and Purification............................................................................... 26 Decanter ....................................................................................................................................... 26 Introduction .............................................................................................................................. 26 Operating Conditions and Geometry .......................................................................................... 26 Distillation Column ...................................................................................................................... 29 Introduction .............................................................................................................................. 29 Design ...................................................................................................................................... 29 UNIT DESCRIPTIONS ....................................................................................................................... 31 UNIT SPECIFICATIONS ................................................................................................................... 38 UTILITY REQUIREMENTS ............................................................................................................. 63 Introduction ...................................................................................................................................... 63 Utilities: ............................................................................................................................................ 63 Cooling Water .............................................................................................................................. 63 Electricity .................................................................................................................................... 64 Steam ........................................................................................................................................... 64 Coal ............................................................................................................................................