SBIR-STTR Award

This project investigates ion implantation for modifying the properties of commercial metal alloys to mitigate the growth of catalytic coke which forms on critical heat transfer surfaces during many important high temperature processes including ethylene cracking, heavy oil refining, partial oxidation and substoichiometric combustion. These coke deposits are generated as byproducts of thermal cracking reactions and diminish heat transfer rates, thermal efficiencies, and reactor product yields. Work will focus on ion implantation of selected periodic elements, such as alkali/alkaline earth, phosphorous and aluminum, into commercial alloys to suppress coke formation by: ( I ) promoting the gasification of carbon, (2) altering the catalytic activity of metals for the formation of carbon radicals, and (3) impeding the process of carburization. Ion implantation offers a more durable method for treating critical heat transfer surfaces competed to conventional coating techniques such as electroplating and plasma spraying because it is less prone to cracking and delamination under extreme thermal environments. In Phase I, the coking rates of ion beam implanted metal coupons will be compared against data for conventional alloys under industrial thermal cracking conditions to assess the effectiveness of this technique. Phase II work will focus on use of emerging ion implantation techniques to allow application to more complex geometries including the inside of commercial furnace tubes.Ion implantation of selected elements to mitigate coke deposits on high temperature metallic surfaces can significantly improve the operating economy and life of heat transfer equipment subjected to thermal cracking conditions. Commercial applications will include treatment of thermal cracking furnace tubes and burner components.

This Small Business Innovation Research(SBIR) Phase II project involves use of ion implantation for modifying the surface properties of metal alloys to mitigate the growth of catalytic coke that forms on furnace tubes during the thermal cracking of hydrocarbons for the production of olefins. Because coke deposits diminish heat transfer rates, thermal efficiencies and product yields, the control of coke growth rate in furnace tubes can significantly enhance the profitability of olefins production. A substantial reduction in the the rate of coke formation on metal coupons by ion implantation of selected elements was demonstrated in Phase I. Ion implantation produces a coke-inhibiting surface layer that is less prone to degradation under the harsh conditions of a thermal cracker compared to pure coatings formed using alternate treatment methods. In Phase II, test specimens will be prepared using a conformal treatment method known as plasma ion immersion implantation and deposition (PIIID), and the effect of implant composition on coke inhibition will be measured using a lab- scale thermal cracking reactor. The method will be used to treat an industrial furnace tube section that will be tested in a pilot-scale coking reactor. The technology developed in this program will lead to treated furnace tubes with substantially increased on-line time, efficiency and product yield for thermal crackers used to produce olefins such as ethylene, propylene and butylene. Coke formation is estimated to cost a modern ethylene facility about $10,000,000 per year.