Measurement of Crude Oil Corrosivity Using Radioactive
Inclusive Dates: 07/01/01 - Current
Background - Technology is needed to determine accurately and quickly potential crude oil corrosivity from the laboratory analysis of crude oil samples. Current methods lack timeliness, reliability, and predictive accuracy, which have led to contradictions between projected and actual corrosion experiences in refining and processing operations. Currently, no comprehensive database exists for assessing true crude oil corrosivity. Traditional estimators, based on sulfur and naphthenic acid concentration measurements, have proven inadequate in defining the true corrosivity potential of specific crudes, and this has proven problematic for buyers and sellers of crudes, and subsequent refiners and processors. As it becomes necessary to process poorer quality crudes, corrosion problems and intricate financial issues will increase, and a premium could be placed on obtaining accurate, time-resolved corrosion data.
Approach - Collectively, the above mentioned factors provide an opportunity to extend SwRI's radioactive tracer technology (RATT®) capabilities to the area of crude oil corrosivity measurement and to develop opportunities for providing corrosivity measurement and corrosion/erosion research and development services. Thus, the research team's focus is twofold: to adapt SwRI's radioactive tracer technology and develop test protocols for making accurate corrosivity measurements and predictions and to establish a capability for providing standardized measurement and enhanced corrosion and erosion research and development services using this technology. The immediate objective is to adapt RATT to the detection and measurement of crude oil corrosivity in a manner conducive to standardized testing and commercial application. The research team is pursuing the application of bulk neutron activation RATT because its high sensitivity should allow the development of a meaningful laboratory test that can economically and relatively quickly characterize the effects of crude oil corrosiveness on selected fluid-handling materials. Such a laboratory setup could be used as a screening tool to rapidly determine which oils are more corrosive than others with respect to specific pipeline materials, and as a research tool for further investigation of corrosion and other material-related issues.
Project efforts are focused in three areas: 1) determining the time-resolved detection limits and corrosion prediction capabilities of RATT when applied to the measurement of crude oil corrosivity, 2) developing bench-top hardware and laboratory testing procedures for applying RATT to crude oil corrosion measurement, and 3) demonstrating corrosivity measurement capability on neutrally, mildly, and highly corrosive crude oils. In addition, the project will serve as a stepping stone for indicating potential for developing laboratory hardware and procedures for measuring real-time corrosion and erosion in piping components under simulated refining and processing operations, with possible extension to real-time, on-site, corrosion measurement and monitoring.
The technical approach is rooted in experience using radioactive tracers to measure real-time wear in operating engines by monitoring lubricating oil radioactivity caused from the accumulation of wear particles abrading from irradiated rings and bearings. Because of RATT's high sensitivity, extremely small changes in wear have been measured. Corrosion detection and measurement are characteristically similar. SwRI experiments will investigate the ability for obtaining meaningful measurements of material degradation by monitoring the radioactive buildup of corrosion debris in the fluid. Initial testing will be performed at elevated temperature (600 °F) under dynamic flows simulating refinery conditions. Data will be obtained through radiometric evaluation of fluid samples periodically withdrawn from the reactor vessel and from on-line measurements obtained from the continuous flow loop. The on-line measurements are important to the evaluation because they provide the means for obtaining corrosion data in real-time.
Accomplishments - Initial test loop designs and testing protocols are being developed to simulate certain refinery conditions. These designs and protocols are being guided by CFD simulations and by an extensive literature search, which was initiated to gain a better understanding of corrosion detection and measurement. Dynamic simulations during experimentation will avoid corrosive film build-up, which could interfere with the corrosion measurements, and will add relevance to the results. Experimentation will be accomplished using activated coupons inserted into confined tangential flows under controlled shear stress conditions.