466662 Sustainable Production of Styrene By Conversion of Benzene and Ethylene through Carbon Dioxide

Monday, November 14, 2016
Grand Ballroom B (Hilton San Francisco Union Square)
Anders Jaksland, Tim B. Hybschmann, Julie N. Larsen and Anjan Kumar Tula, Technical University of Denmark, Kgs. Lyngby, Denmark

The demand of styrene is increasing more than the capacity, thus new, sustainable, and energy-saving
processes are highly requested. When ethylbenzene is dehydrogenated with CO2 to produce styrene, the
process is more ecological and economical than when water is used[1].
The aim of this project is to develop sustainable design for styrene production. The economic feasibility, the
sustainability issues together with the ethylbenzene:carbon dioxide ratio are investigated. A systematic
sustainable process design method consisting of 12 hierarchical tasks are performed to obtain the final
sustainable process design.
The starting point is a survey to collect data from which the raw material and the corresponding conversion
reaction are selected for the product to be made, which is styrene. Benzene and ethylene are selected as
raw material and a carbon dioxide route instead of the well-known water route is selected for the
conversion steps. A quick economic potential calculation is made to ensure a profitable starting point. The
next set of tasks help to identify the processing route (solve the process synthesis problem) and to obtain
the base case design. To reach this point, first mass balance with simple models; then mass and energy
balance to establish the operating conditions, also with simple models; then simulation with rigorous
models; and finally, sizing and costing calculations are performed. The base case design is found to be
economically infeasible. However, the next set of tasks determine the sustainable design through targeted
improvement of the base case design through heat-mass integration, design optimization as well as
evaluation of environmental impacts. The final design gives a more sustainable process design.
The standard computational tools – process simulator (PROII), economic analysis (ECON[2]), sustainability
analysis (SustainPro[2]) and lifecycle assessment (LCSoft[2]) together with well-known methods for heat-mass
integration and sustainable process design[3].
The main features of this design are: a high conversion of benzene and ethylene to a higher value product,
more energetically favorable reaction conditions through carbon dioxide utilization, and removal of
byproducts for a 99.8% pure styrene product.
The work was done as part of a chemical process design course4 and extended after to reach the final more
sustainable design.

1 Andressa H. de Morais Batista, et al. Ethylbenzene to chemicals: Catalytic conversion of ethylbenzene into styrene
over metal-containing mcm-41. Journal of Molecular Catalysis A-chemical, 315(1):86-98, 2010.
2 Kalakul, S, Malakul, P, Siemanond, K, Gani, R, “Integrated of Life Cycle Assessment Software with Tools for Economic
and Sustainability Analyses and Process Simulation for Sustainable Process Design”, Journal of Cleaner Production,
2014, 71, 98-109
3 Babi, DK, Teaching Sustainable Process Design using 12 systematic Computer Aided Tasks, Computer Aided Chemical
Engineering, 2015, 37, 173-178.
4 Process Design: Methods and Principles, MSc-course (C28350), Technical University of Denmark, Lyngby, Denmark

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See more of this Session: Interactive Session: Systems and Process Design
See more of this Group/Topical: Computing and Systems Technology Division