The copper strip corrosion test (CSCT) is used to measure the corrosivity of sulfur compounds in fluids. The CSCT is performed by immersing a strip of cleaned, polished copper in a fluid at a specified temperature for a predetermined time, then reading the strip against a standard. In this work, instead of using the usual large, oblong strips designed to measure 30 mL fluid samples, we used small circular Cu coupons as an alternative method for carrying out CSCTs on microscale samples of fluid. The motivations for reducing the scale include: applicability to small samples, ability to archive the small and inexpensive coupons, reduced waste, and potential for automated analysis using autosampler vials as reaction vessels. Moreover, the symmetric circular geometry facilitates the analysis of the images with mathematical colour spaces. Mixtures of n-decane:n-tetradecane with varying concentrations of H2S (from a distillation column) were used as a source of microscale samples of corrosive fluid to demonstrate the viability of the smaller scale CSCT. Additional experimental details concerning the lighting conditions and digital photography of the coupons, measurement of corrosion using colour space, and quantitation of the total sulfur content of the distillate are also described.
Citation: J. Sulfur Chem.
Pub Type: Journals
colour space, copper strip corrosion test, sulfur impurities