Characterization and preliminary root cause identification of black powder content in a gas transmission network – A case study

• Black powder (BP) is a global operational problem in gas industry.
• Global black powder experience and associated issues & challenges are highlighted.
• Chemical characterization of black powder samples from pipelines is provided.
• Root-cause assessment of BP formation is made from three gas treating units.
• High H2S levels and potential liquid carryover in gas distribution lines could be one major cause for BP generation.

Black powder is a global issue faced by almost all gas producing countries. Understanding characteristics and nature of black powder is required for successful pipeline operations and to assess root-cause of its formation. This paper is mainly divided into two parts. First part gives a synopsis of the global black powder experience and summarizes associated issues and challenges. Second part of the current study is dedicated to chemical characterization of black powder samples received from a sales gas pipeline and root-cause assessment of its formation in a gas processing plant in the Middle East. Elemental analysis of black powder samples show presence of mainly iron and sulfur with traces of various other elements. Further analysis shows presence of both iron sulfides and iron oxides in the network. Root-cause assessment measurements are made from three gas treating and dehydration units in a gas processing plant. Analysis of about 5 month's data indicated that the H2S levels in one of the trains were 3–4 times higher than the other two trains. Assessment analysis points to the possibility of black powder being generated in some processing units and in the sales gas pipeline.