Polyethylene: Manufacturing Cycle and Environmental Impact

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Manufacturing Cycle and Environmental Impact

The most common form of polyethylene is petroleum based or olefins based; as before mentioned polyethylene compounds have a wide commercial applicability and are made from non-renewable resources (Harding, Dennis, von Blottnitz, Harrison, & S.T.L., 2007). Its manufacturing processes are regarded as energy intensive and release significant amount of CO2 and heat into the atmosphere (Broderick, 2008). Next a little more detailed description of polyethylene’s production processes will be presented, with a focus on the way the material inputs are extracted and synthesized.

First step to produce polyethylene is to obtain the ethane from the ground. Ethane can be obtained either by extraction from natural gas or from crude oil using a process called fractional distillation (AUS-e-TUTE n.d.; University of Washington). Fractional distillation is a process that separates the various components of crude oil, in this case, to obtain ethane.

After the oil/gas mixture is drawn from the ground, it is then stored into a storage tank and allowed to rest for a while. Then the gas is piped off to a set of distillation columns to clean up the ethane. In order to activate the chemical reaction necessary to separate the ethane, a thermal cracking unit (a sort of long heated tube) i.e. a plug flow reactor is used. After a series of distillations, ethylene exits the tube.

Before using ethylene to produce polyethylene, the compound needs to be purified to almost 100%. In order to reach this level of purity the ethylene needs to be freed of olefins, acetylenes, dienes and water through several processes such as: driers are used to take out the water, a demethanizer is used to remove methane, etc. ...

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...onough, W., & Braungart, M. (2002). Cradle to Cradle. New York: North Point Press.

National Center for Manufacturing Sciences. (2004, August 11). Environmental Roadmapping Initiative. Retrieved October 14, 2011, from Plastics Impacts, Risks and Regulations: http://ecm.ncms.org/ERI/new/IRRPlastics.htm

Piringer, O., & Baner, A. (2008). Plastic packaging: interactions with good and pharmaceuticals. New York: Wiley-VCH.

Siemens. (2007). Process Analytics in Polyehylene (PE) Plants. Houston: Siemens AG.

Stephenson, R., & Blackburn, J. J. (1998). The Industrial Wastewater Systems Handbook. New York: Lewis Publishers.

UNEP. (2001). Environmental Technology Assessment; Case Study – Polyethylene Production.

University of Washington. (n.d.). The World of Polyethylene. Retrieved October 14, 2011, from http://faculty.washington.edu/finlayso/Polyeth/Group_B/techintro.html

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