Comprehensive Plant-Wide Real Time Optimization of a World-Class Ammonia Plant

C. RASPANTI; M. ROSSI; A. BANDONI; D. BORIO; M. MEIXEL

Washington DC

Congreso; OPTIMIZE 2011; 2011

Aspen Tech

This real time optimization (RTO) application is comprehensive, including all the ammonia plant process-side equipment as well as the fuel and flue gas side heat recovery, and steam system units.  Furthermore, sufficient detail of the urea plant, which is consuming the ammonia plant’s product ammonia and carbon dioxide, in included to account for the highly coupled steam systems of the ammonia and urea plants.  High fidelity models are used, especially for the reactors (primary and secondary steam reformers, high temperature water gas shift, low temperature water gas shift, methanation, and ammonia synthesis), as well as for the carbon dioxide removal system.  The CO2 removal system is an MDEA (methyl diethanolamine) based system, and the model includes the electrolyte and chemisorption reactions in the MDEA absorber and solution regenerators.  The RTO application also performs an ongoing equipment and process monitoring function.  The RTO system is closely coupled with a plant-wide multivariable advanced process control system.  The application has been in closed-loop operation for several months and is performing robustly, with a service factor of almost 100 % since January 2011. The application was developed jointly by AspenTech, PLAPIQUI, and PROFERTIL staff.