Organic neutralizing amines are commonly used to combat corrosion in refinery crude column overhead systems. Yet under-deposit corrosion and active acid corrosion are frequently reported in such refinery process units. Several of these failures can be traced to poor application, or misuse, of organic neutralizing amines. The common cause is usually a lack of understanding of the electrolytic thermodynamics, thermochemical properties and/or phase equilibria of these organic amines. To understand the root cause(s) of these failures, a rigorous, fundamental, thermo-dynamic approach was developed in Shell Oil. Important thermochemical and physical properties were identified and phase equilibria relevant to a typical crude unit overhead were outlined. Custom-developed apparatus and experimental procedures were used to measure the needed data and to validate thermodynamic consistencies. These methodologies and data generation techniques will be described here. The incorporation of these data into the frame work of commercial flowsheeters such as ProVision(R) (electrolytes) and Aspen Plus(R) (with OLI Engine(R)) will also be discussed. The use of commercial flowsheeters is the recommended way to practice our rigorous technology in the field. Complementary forms of output such as Charts, Nomographs, Spreadsheets and Phase Diagrams can also be produced and used by field staff. To successfully apply this technology to refinery crude column overheads in Shell and non-Shell crude towers, we set up a Technology Partnership Program, with a chemical supplier-Baker Petrolite. This relationship has proved to be very successful in the USA and will be outlined. ('ProVision', 'AspenPlus' and 'OLI Engine' are registered trademarks of Simulation Sciences, Aspen Technology and OLI Systems.)