(465a) Environmental and Techno-Economic Analysis for Ethylene Production from Shale Gas

Andrea Paulina Ortiz Espinoza ^a, Arturo Jiménez Gutiérrez ^a, Mahmoud M. El-Halgawi ^b

^a Departamento de Ingeniería Química, Instituto Tecnológico de Celaya, Celaya, Gto., Mex., 38010

^b Chemical Engineering Department, Texas A&M University, College Station, TX 77843, USA

Ethylene is a light olefin that is used as a large building block for many petrochemicals. It works as the raw material in the manufacture of several products such as plastics, resins, fibers, etc. Ethylene is typically produced from thermal cracking of naphtha or ethane and propane from natural gas. In the thermal cracking, valuable by products including propylene, butadiene, and benzene are also produced in significant amounts. Besides the conventional process used to produce ethylene, alternative methods have been developed, some of them using methane as a feedstock.¹ These particular processes have been gaining importance due to the lower prices of natural gas and most recently shale gas discoveries.

One of these methods is the Oxidative Coupling of methane, which involves direct conversion of methane to ethylene by using a catalytic reactor. This process has been investigated for about 30 years and has not been industrially implemented due to its medium conversion and low selectivity. Despite this, the process is a very promising alternative for the production of ethylene from methane that is worth of consideration.² Another process that has been developed for the production of ethylene is the Methanol to Olefins process. In this process, methane is converted to syngas through a reforming reactor, and then the syngas is converted to methanol in a catalytic reactor. Once the crude methanol is obtained it is converted to ethylene.³

This work presents a techno-economic analysis and comparison of the above mentioned alternatives to produce ethylene. An environmental assessment for each process is also carried out in order to show the advantages and limitations of these alternatives. First, Aspen Plus® simulations are developed to obtain mass and energy balances. Then, along with data reported in literature, return on investment is calculated to show the profitability of each process. Finally CO₂ emissions are calculated to assess the environmental impact for the processes. The results identify the compromise between economics and environmental implications for these production alternatives.

1. Sundaram, K.M.; Shreehan, M.M.; Olszewski, E.F. 2010. Ethylene. Kirk-Othmer Encyclopedia of Chemical Technology, 1-39.

2. Godini, H.; Xiao, S.; Jašo, S.; Stünkel, S.; Salerno, D.; Son, N.; Song, S.; Wozny, G., 2013. Techno-economic analysis of integrating the methane oxidative coupling and methane reforming processes. Fuel Processing Technology, 106, 684–694.

3. Ren, T.; Patel, M.K.; Blok, K. 2006. Steam cracking and methanol to olefins: energy use, CO₂ emissions and productions costs. Energy, 33, 817-833.