Effect of Ethanol Blends and Batching Operations on Stress Corrosion Cracking of Carbon Steel

Main Objective

Categorize ethanol blends into three categories: blends that can be transported in existing pipelines without significant modification of the system and operations (Category 1), blends that require significant modifications (Category 2), and blends that cannot be transported in existing pipelines, but could be moved in specially designed systems (Category 3).Develop data necessary to make engineering assessments of the feasibility of transporting fuel-grade ethanol (FGE) and FGE blends in existing pipelines in a batching or dedicated mode.

Public Abstract

Pipeline transportation of ethanol is vital to the cost effective delivery of this fuel to the end-users. One of the main concerns in the transportation of the ethanol is the potential for stress corrosion cracking (SCC) of steel in the presence of ethanol that can lead to ethanol leakage and release. Previous studies conducted by the project team have shown that the propensity of steel to crack decreases if gasoline content exceeds a certain value, depending on the ethanol source. Therefore, transportation of certain blends may be possible in existing pipelines without any operational changes. Furthermore, it is not clear whether a pipeline operated in a batching mode would suffer from SCC. This may depend on the residence time of ethanol, the batches of liquids sent before sending an ethanol batch, and crack growth rates. Finally, the performance of elastomeric seals and gaskets in ethanol is an important factor in pipeline integrity. This research project aims to develop guidelines for the maximum ethanol/gasoline blend that can be transported in existing pipelines, safe batching modes of operation, acceptable gasket and seal materials, and mitigation methods for SCC that will have minimal impact on end-use. The major benefit of the project is the development of comprehensive guidelines that could be used to develop ethanol transportation standards. This Consolidated Program consists of this project and Project 246 and Project 248.

Final Report

Final Report-WP325

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