Monitor Active Vapor Corrosion Inhibitors in Tank Pads

Overview

Main Objective

The objective of this research project is to develop new monitoring technology for the presence and effectiveness of VCI installed in aboveground storage tank floors.

Public Abstract

Project Description: Soil-side corrosion is one threat to the integrity of breakout tanks, and VCIs are an alternative corrosion control measure to cathodic protection (CP) that has been widely used by tank operators with mixed success. Tank operators are increasingly using VCIs either standalone or in combination with CP for aboveground storage tanks (AST). Research has shown that VCIs can provide effective protection from corrosion when used properly and in sufficient quantities. However, monitoring VCIs' effectiveness is not straightforward. Industry standards and best practices have established some provisions for monitoring VCIs effectiveness and their replenishment timeframe, but more rigorous procedures and methods need to be established to achieve optimal corrosion control from VCI technology. While a thorough floor plate inspection can provide a direct measure of the VCI's effectiveness, it is not practical while the tank is in-service, and VCIs' performance evaluations are necessary in-between inspection schedules. Therefore, methods, processes, and technological enhancements are needed to evaluate VCIs' performance effectiveness during in-service conditions. Additionally, project work will also focus on establishing a cost-effective methodology to calculate timetables for the replenishment of VCIs.

This research will be comprised of large-scale and field-testing utilizing VCI-treated in-service ASTs, with laboratory testing and evaluations. A set of laboratory experiments will be setup to precisely identify effective VCIs concentrations by measuring the corrosion rates and chemical markers associated with VCI chemistries. Large-scale experiments will be conducted to study the rate of VCIs' escape under a typical tank condition. Field sand samples will be collected from the tanks that have been treated with VCIs, and monitoring data from those tanks will also be studied. Data from the laboratory, large-scale and field-testing will be used to develop methods and process to measure the VCIs' effectiveness in field conditions. In addition, as determined using the chemical marker concentrations and associated corrosion rate, the VCIs' escape rate data will be used for establishing a cost-effective methodology to calculate VCI replenishment timetable.

Anticipated Results: Methods will be developed for directly measuring VCI concentrations, which will be correlated to the level of protection being provided by the VCIs. This will directly help operators determine the need for VCI replenishment or additional sampling. Most importantly, the project will result in the generation of knowledge and in-depth understanding of VCI technology that operators can directly use in field implementation, and thereby improve life-cycle performance of AST bottoms.

Potential Impact on Safety: Corrosion induced integrity breaches of breakout tank bottoms result in the release of hazardous liquids, which can migrate into the biosphere if the secondary containment is compromised; leakage of hazardous liquids into the biosphere could have an adverse effect on public health and safety. VCI technology is an alternative corrosion control tool to CP, and can be used standalone or in combination with CP. This project will help tank operators to optimally apply VCI technology and monitor the associated parameters that meet the corrosion control performance criteria, and thus help enhance the safe operation of ASTs.

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