Improving corrosion resistance of welded radiant and convection coiled-pipes in pipe stills at «Kinef» oil refinery

Improving corrosion resistance of heating pipe stills with the use of a special corrosion inhibitor SNPH - 6030 “B” is an economical method and is very important for the oil industry, since complete replacement of damaged by corrosion pipe still coils is a very costly process. The presence of heavy metals, metal compounds and other impurities in crude oil adversely affects the corrosion resistance of oil refinery equipment and installations. Modern methods used in the study including chemical analysis and atomic absorption spectroscopy (using VARIAN-SPECTRA AA 220 FS device) were carried out with the application of an analytical scanning (raster) electron microscope VEGA3 TESCAN. Micro X-ray spectral analysis of the composition of phases present in coiled-pipe materials was carried out by the method of energy dispersive x-ray spectroscopy on Oxford INCA Energy EDS spectrometer. The method of weight loss was used to analyze the corrosion ability of the coil. The conducted studies have shown the formation of pitting corrosion that can be attributed to the electrochemical type. The proposed inhibitor is effective in terms of increasing the corrosion resistance of pipe still coil material due to corrosion rate reduction. The best results were achieved using the selected inhibitor under the following conditions: duration ̶ 48 h, inhibitor concentration - 0,02 wt.%, temperature - 100 °C; effectiveness of corrosion rate reduction under these conditions reached 97,94%.

oil refinery, coiled-pipe, heating pipe still, corrosion, inhibitor, crude oil