2016 Annual Meeting

November 8 - 13, 2015

448752                Troubleshooting for Catalysts in Ammonia Plant Reactors.                                                           Dr. Mohamed Abdel Aaty*- (Technical review about catalysts deactivation with a case study for temporary poisoning in ammonia Synthesis converter catalysts).  Catalysts Have Only a Limited Lifetime. Some Lose Their Activity after a Few Minutes, Others Last for More Than Ten Years. the Maintenance of Catalyst Activity for As Long As Possible Is of Major Economic Importance in Industry. the Causes of Deactivation Are Basically Three-Fold:Chemical, Mechanical and Thermal. the Development during the Past Two Decades of More Sophisticated Surface Spectroscopies and Powerful Computer Technologies Provides Opportunities for Obtaining Substantially Better Understanding of Deactivation Mechanisms.  a Decline in Activity during the Process Can be the Result of Various Physical and Chemical Factors like Blocking of the Catalytically Active Sites and Loss of Catalytically Active Sites Due to the Following Mechanisms.the Mechanisms of Catalyst Deactivation in Ammonia Plant Can be Classified into Different Common Types: (i) Poisoning, (ii) Coking, (iii) Thermal Degradation, (iv) Vapor Compound Formation Accompanied By Transport.  Typical Poisons Are H2S, Pb, Hg, S, P in Primary Reformer and Low Shift, Coke and Deposits on the Catalyst Surface Block the Active Centers and Change the Pore Structure, Thermal Processes and Sintering of the Catalyst Lead to a Loss of Active Surface Area and Catalyst Losses By Evaporation of Components (e. g., formation of volatile metal carbonyls with CO in methanation reaction).  a Brief Discussion about Phenomena of Catalysts Deactivation to Understand These Deactivation Mechanisms, and Illustrate a Case Study about Temporary Ammonia Catalysts Poisoning from Syn. Compressor Lube Oil Escaping and Analysis for the Ammonia Synthesis Converter Catalyst Has Been Carried out Using Hysis Software. This Software Allows an Assessment of the Catalyst Activity Based on Our Kinetic Models