HELIUM
Your name
Your institution

Author note.
Assignment submitted by [Your Name] for [Your course]

Introduction
Helium is a colourless element that is chemically inert. Although helium is the second most abundant element in the universe after Hydrogen, most of it is found outside the earth atmosphere. Since it is chemically inert, Helium is used in arc welding and in preparation of silicon and germanium where a non-reactive environment is required. The inertness of helium gives it the ability to be used to prevent sparking, ignition or explosions due to rubbing in environments abundant of oxygen. (Karasik, Messins, Cooper, & Heald, 2001, p.400).
Raw Materials
Helium comes as a direct result of radioactive decay of some elements. After radioactive decay has occurred helium escapes from this elements and mixes with the natural gases that form there. Since it’s extremely light, Most of it escapes out of the earth’s atmosphere into the space (Vardiman 1986). Therefore there are two sources of helium; air and natural gases. This means that there also two ways through which Helium can be produced; through liquefaction of air and the processing from natural gases. The later is preferred because the significant amount of helium in natural gas and the fair cost of production compared to liquefaction.
The Manufacturing Process
The composition of natural gases is mainly methane, propane, butane, nitrogen, oxygen, carbon dioxide, hydrogen sulfide and helium (Bakar & Ali, p.1). Some of the constituents of natural gas are impurities which lowers its overall heat energy. To avert this problem, upgrading of the natural gas is done. This process eliminates the known impurities. The various processes used are dependent on the level and types of impurities in the gas.
When the level of helium is above 0.4%, cryogenic distillation is used so as to extract helium. Once this has been accomplished helium undergoes the process until it attains the commercially acceptable purity. The diagram below elaborates the manufacturing process.

Figure 1: How Products are made. adapted from Madehow, by Chris Chieve, Retrieved October 28, 2009, from http://www.madehow.com/Volume-4/Helium.html
Pre-treating
The process of pre-treating begins with the subjection of the natural gas to a pressure of 800 psi before being passed mono-ethanolamine which removes traces of carbon dioxide from the gas. Water in the mixture is removed through a molecular sieve while Hydrocarbons are eliminated when the mixture is passed through a bed of activated carbon. (Linde, 2007, p. 6)
At this stage only methane, nitrogen, hydrogen, helium and neon are the remaining products.
Separating
The separation of nitrogen and methane from the rest of the components of natural gas is done at this stage. To do the separation, the gas stream is passed through a valve which makes the gas to expand while the pressure drops. The result is that methane liquefies. It is now passed through a high pressure fractionating column. As the mixture ascends, nitrogen further liquefies and thus forms the lower layer of the fractionating column. Liquid methane is drawn out at this point and subjected to the same process so as to remove any remaining impurities.
The remaining gas in the column is passed through a condenser which cools the content. Nitrogen condenses and is extracted as vapour leaving behind a mixture that is mostly composed of helium. (Linde, 2007, p. 10)

Purification
At this stage helium is super cooled to a temperature of -193oC. This temperature is too low and any nitrogen or methane available condenses and is removed. Air is then passed through the mixture before being passed a catalyst. The Hydrogen in the mixture reacts with oxygen to form water molecules. The gas is then cooled leading to the removal of water molecules from the mixture. Purification ends with the mixture being passed through a Pressure Swing absorption unit. . (Linde, 2007, p. 10)

Figure 2: How Products are made. adapted from Madehow, by Chris Chieve, Retrieved October 28, 2009, from http://www.madehow.com/Volume-4/Helium.html

References
Bakar, W.A. and Ali, R. Natural gas. Department of Chemistry, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia.
Karassik, I. J., Messina, J.P., Cooper, P., Heald, C.C. (eds). (2001). Pumb Handbook(3rd ed.). New York, NY: McGraw-Hill Books Publisher.
Linde Group. (2007). Natural Gas Processing Plants. [web]. 3-11 Retrieved from http://www.linde-engineering.com/internet.global.lindeengineering.global/en/images/HE_1_1_e_12_150dpi19_4271.pdf. Vardiman, L. (1986). The Age of the Earth’s Atmosphere Estimated by its Helium Content. Pittsburgh, PA: Creation Science Fellowship, Inc.