英语翻译
PREDICTION AND ASSESSMENT OF AMMONIUM BISULFIDE CORROSION
UNDER REFINERY SOUR WATER SERVICE CONDITIONS
ABSTRACT
This paper summarizes results of Phase II of a joint industry program (JIP) that addressed ammonium bisulfide (NH4HS) corrosion.This phase of the program was focused on NH3-dominated sour waters typically found in refinery services such as the overhead systems of some sour water stripper units.Phase II extended the initial research work in Phase I of the program,commonly referred to as the Sour Water JIP,which addressed NH4HS corrosion in H2S-dominated sour waters.This Phase II work in NH3-dominated sour waters studied the impact of several process variables including NH4HS concentration,NH3 partial pressure,H2S partial pressure,temperature,cyanide concentration,and velocity (wall shear stress).Data collected from laboratory tests designed to characterize these process variables were used to develop an enhanced software tool to predict corrosion rates for six materials evaluated in the program.Key aspects of the data,parametric behavior,and corrosion response of the different materials evaluated in the Phase II work are highlighted in this paper.
Keywords:sour water,ammonium bisulfide,NH4HS,hydrogen sulfide,H2S,ammonia,NH3,partial pressure,isocorrosion diagram,temperature,cyanide,velocity,wall shear stress,materials selection,software,sour waterstripper.
INTRODUCTION
For several decades the selection of materials of construction to resist ammonium bisulfide (NH4HS) corrosion was primarily based on empirical findings that relied heavily on evaluations of operational experience,along with very limited controlled laboratory tests.Limits on material utilization were for the most part very general guidelines,usually based on the NH4HS concentration and velocity of the sour water stream containing the NH4HS.However,in March 2000 a joint industry program (JIP) titled “Prediction and Assessment of Ammonium Bisulfide Corrosion Under Refinery Sour Water Service Conditions” was initiated to develop a quantitative engineering database and provide guidelines to predict corrosion in hydrogen sulfide (H2S)-dominated alkaline sour water systems typically found in refinery services such as the reactor effluent air cooler systems of hydroprocessing units.Phase I of the program,commonly referred to as the Sour Water JIP,was completed in March 2003 and the results were reported to the 16 sponsors in June 2003.The Sour Water JIP used a specialized laboratory flow loop designed specifically to develop corrosion data for 14 materials exposed to well-defined and controlled alkaline sour water environments.