(67c) The Safe Use of Copper -Containing Catalysts in Ethylene Plants

Copper-containing catalysts are used in a wide range of applications by the petrochemical industry. A number of these applications involve acetylene and/or other acetylenic species. The reaction of acetylene with copper under certain conditions can form copper acetylides, and depending on the process environment, a potentially unstable mass of copper acetylides may result. On the other hand, a catalyst comprising highly-dispersed copper in a stable matrix, if used in a non-leaching process, can be employed in acetylene-containing services with no risk from copper acetylides.

Applications for which copper-containing catalysts are of interest among both producers and consumers of ethylene, include the removal of various impurities ? by chemisorption and by hydrogenation ? from ethylene, propylene, refinery offgas, and other streams encountered in plants producing olefins and polyolefins. And in most of these applications, some levels of acetylene(s) are present.

Nevertheless an erroneous perception exists in the industry, that copper acetylide formation is a safety risk wherever copper-containing catalysts may come in contact with acetylenes - regardless of the nature of the process or catalyst.

This paper will explain the difference between process environments in which copper-containing catalysts may be used with no risk from copper acetylides, and those in which a copper acetylide mass with the potential for deflagration may occur. This paper will include BASF's investigations into the formation of copper acetylides in its olefin purification catalysts, including measurements on the amounts of copper acetylides which can form, and measurements on their potential for explosivity by an independent expert. In addition, it will discuss various other safety considerations regarding the use of copper catalysts.