Benzene-Toluene-Xylene Production Process from Liquefied Petroleum Gas Using Aspen HYSYS and Aspen Energy Analyzer

International Journal of Research and Scientific Innovation (IJRSI) | Volume VI, Issue VIII, August 2019 | ISSN 2321–2705

 Benzene-Toluene-Xylene Production Process from Liquefied Petroleum Gas Using Aspen HYSYS and Aspen Energy Analyzer

U. S Ubam^1*, A Bello², U. D Amoka³, A. G Adamu⁴

^1,3,4 Chemical Engineering Department, Ahmadu Bello University, Zaria, Nigeria
² Department of Chemical Engineering Technology, Federal Polytechnic, Nasarawa, Nigeria
*Corresponding Author

Abstract: – In this work, Aspen HYSYS simulation software was used to develop a process for Benzene-toluene-xylene BTX synthesis; a leading feedstock in the petrochemical industries for the synthesis of several chemicals, from liquefied petroleum gas LPG. The pinch and retrofit analysis as applicable to the developed model was carried out using Energy Analyser V10 in order to develop a network of heat exchanger, possible energy savings and payback period of the process. The result of the simulation showed that benzene, toluene and xylene have compositions of 89.3%, 95.5%, and 100% respectively suggesting that the process is highly favoured by low pressure and high reflux ratio. The energy analysis revealed that fifteen (15) heat exchanger network (HEN) were developed comprising of seven (7) heaters and eight (8) coolers for the base case simulation and about 0.6MWof wasted heat was recovered by incorporating three (3) additional heat exchangers to the base HEN leading to 9.6% total energy savings of the entire system. The retrofit design suggested three case scenarios yielding payback periods of 2.062 years, 1.802 years and 6.579 years respectively among which the one the second case scenario with 1.802 years was selected to be the preferred case scenario.

Keywords: Aspen HYSYS, Pressure, Reflux, Aspen Energy Analyzer, Heat Exchanger Network (HEN), retrofit.

I. INTRODUCTION

Aromatization of liquefied petroleum gas (LPG) to benzene, toluene and xylene (BTX) has drawn attentions to process engineers since it was proven to produce high purity BTX using Aspen HYSYS[1]. BTX have several applications in the synthesis of other chemicals especially petrochemical products like nylon, detergents, paints, drugs, glues etc. and also to the extraction of benzene and blending of gasoline [2]. The process follows the cycler process for synthesis using naphtha feedstock with high demand of energy and low product purity[3][4].Because of sulfur treatment prior to naptha reforming, the cost of production of BTX becomes unreasonably expensive [5]. The introduction of low chain alkanes produces higher purity BTX in comparism to naphtha feedstock [3].

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