Abstract
Sales gas pipeline systems with large diameters and long pipeline lengths can experience the formation of large quantities of corrosion products commonly known as “black powder”. A variety of iron oxides, iron carbonates, iron sulfides, and other contaminants comprise black powder. Black powder formation can be caused by the presence of corrosive gases, including oxygen, carbon dioxide, or hydrogen sulfide dissolved in condensed water in the lines.
Generally, pipeline companies practice various methods to manage and control black powder in their gas network. These methods can be divided broadly into three categories: (a) removal, (b) mitigation, and (c) prevention methods. Mitigation with corrosion inhibitors is typically practiced in lines transporting wet sour gas, and is not normally practiced in sales gas lines.
This paper describes a research study conducted to assess the performance of 14 commercial and specially formulated inhibitors proposed to mitigate the formation of iron oxide based black powder under simulated sales gas conditions. Special, in-house developed, test methods were used to evaluate these inhibitors. Two inhibitors have passed these tests showing a corrosion inhibition effectiveness of approximately 90% and no pitting attack under the simulated sales gas environment.
