Abstract:

This paper introduces five SCR ammonia preparation processes, i.e., liquid ammonia / ammonia water vaporization, urea hydrolysis, urea pyrolysis, ammonia direct injection and urea direct injection. Based on the characteristics of ethylene cracking furnace, these processes are analyzed and compared from the aspects of safety and environmental risk, ammonia conversion rate, system responsiveness and comprehensive cost. None of these ammonia preparation processes can improve the safety and environmental risk level of ethylene plant. Liquid ammonia vaporization method has the best system responsiveness and the lowest economic cost. It is concluded that liquid ammonia vaporization is the preferred SCR ammonia preparation process for ethylene cracking furnace.

Key words: ethylene')">

ethylene, NO_X, SCR, liquid ammonia, ammonia water, urea