Ethylene is one of the most important petrochemical intermediates and feedstocks for many different products. The motivating force of this work is to compare a new process of ethylene production developed at Texas A&M University to the most common processes. Ethylene is produced commercially using a wide variety of feedstocks ranging from ethane to heavy fuel oils. Of them, the thermal cracking of ethane and propane using a fired tubular heater is the most common process in the United States. In Europe and Japan, where natural gas is not abundant, thermal cracking of naphtha using a fired heater is the most common process. In addition to these processes; ethylene could also be produced from crude oil by autothermic and fluidized bed techniques and from coal and heavy oils by synthesis from carbon monoxide and hydrogen. At Texas A&M University, a group of researchers developed a new process that can convert natural gas into liquids (GTL) or to ethylene (GTE). This technology is a direct conversion method that does not require producing syngas. When selecting a process for ethylene production, the dominant factor is the selection of hydrocarbon feedstocks. Based upon plant capacity of 321 million pounds of ethylene per year, this study has shown that using natural gas, as a feedstock, is more economical than using ethane, propane, naphtha, and other feedstocks. Therefore, it is more economical to convert natural gas directly to ethylene than separating ethane or propane from natural gas and then converting it to ethylene. A process simulation package ProMax is used to run the GTE process; and a software program, Capcost, is used to evaluate fixed capital costs of the GTE process. Finally, the cost index is used to update the cost of the other processes of ethylene production today.

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Abstract The oligomerisation of ethylene into products in the C4±C20 range over heterogeneous nickel catalysts in a ®xed-bed reactor at low temperature and high pressure (LT-HP) is reported. The catalysts were obtained by Ni(II) exchange or impregnation of two differently prepared amorphous and mesoporous silica±alumina supports. A plot of catalytic activity versus temperature at 35 bar and MHSVˆ2 produces a volcano-type curve with a maximum around 1208C. Experiments performed under the LT-HP reaction conditions, viz. 1208C, 35 bar and MHSVˆ2, give an ethylene conversion level of 99% and a 97% selectivity to products with an even number of carbon atoms. The product spectrum (Cn distribution) was dependent on the type of catalyst used, with the percentage of the C10‡ oligomers lying in the range 23±41% by mass. Of practical signi®cance, these types of catalyst were found to be extremely stable in use showing no detectable drop in conversion after 108 days on stream under the LT-HP reaction conditions employed.

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb. 12, 2008). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. Shuqun Zhang, Thesis Supervisor. Vita. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 104-110).

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Thesis (Ph. D.)--University of Wisconsin--Madison, 1937. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 205-216).

Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, December 2006. / Thesis Advisor(s): Christopher M. Brophy. "December 2006." Includes bibliographical references (p. 97). Also available in print.