The Black Powder in gas and associated processing equipment is a global phenomenon that many operating companies had and still suffering from. The composition of Black Powder has been found to vary significantly in chemical composition. However, the constituents mainly consist of iron sulfides (FeS) and iron oxides.
Black Powder is known to cause serious problems to pipelines, such as flow inefficiency, product contamination, wear, plugging, and under deposit corrosion. Another major concern is the possible formation of elemental sulfur, which could be produced as a by-product of oxidation of iron sulfides. It also can be produced from H2S dissociation at elevated temperatures or by microbiological reactions involving the reduction of sulfate.
Black powder also presents another problem for the collected deposit samples (in equipment, piping, or cleaning pigging of pipelines) as they are sometimes left exposed to the environment for prolonged periods, and analysis of the deposits shows the presence of elemental sulfur. In these situations, it is not clear whether the elemental sulfur is present due to process contamination or due to exposure to the environment.
To investigate this, a study of Black Powder deposits was carried out to determine the effect of exposure to air at different lengths of time (6 hours, one day, one week, two weeks and three weeks) for atmospheric conditions, and at higher temperature (50°C) for the same samples at the same lengths of time. This will enable better understanding of the formation of elemental sulfur for black powder deposits. The results of this study are presented in this paper.
Black Powder is a phenomenon that all oil and gas companies are facing and presenting a variety of problems in associated processing equipment and pipelines, such as flow inefficiency, product contamination, wear, plugging and under deposit corrosion, among others.
Another major concern is the possible formation of elemental Sulfur (S8), which could be produced as a by-product of oxidation of iron sulfides. It also can be produced from H2S dissociation at elevated temperatures or by microbiological reactions, involving the reduction of sulfate.