Corrosion-Fouling of 316 Stainless Steel and Pure Iron by Hot Oil

Abstract

We examined the fouling and corrosion that took place when 316 stainless steel and pure iron wires were electrically heated to 540À680°C in a liquid bath of the atmospheric bottoms fraction of a crude oil. The foulant was determined to be heterogeneous, with a thick macroscale outer layer of pitch, covering a microscale sheath of coke, which was in turn both covering and interspersed with a microscale layer of iron sulfide. This foulant was observed to delaminate from the wire surface, presumably as a result of both the generation of growth stresses and the action of gas bubbles that were evolved during the fouling process. Unexpectedly but conclusively, we observed that the underlying wire surface was heavily corroded. In the case of the stainless steel, we observed a microscale chromium oxide layer that separated the foulant from the underlying metal. This layer presumably reduced the rate of metal dissolution. The degree of corrosion was much higher in the pure iron samples, where such a layer did not exist. Our hypothesis is that there is a synergy between the measured macroscopic fouling and the underlying microscopic corrosion, where the iron from the wire reacts with the sulfur in the oil to build up the thick sulfide.

Silicon nanowire core aluminum shell coaxial nanocomposites for lithium ion battery anodes grown with and without a TiN interlayer

“…One would not expect the Cr 2 O 3 to be reduced by the H 2 present during the Si NW growth process due to its very high thermodynamic stability {2Cr(s) + 3H 2 O(g) 0 Cr 2 O 3 (s) + 3H 2 (g), DG ¼ À298.5 kJ mol À1 }. 36 A slightly lower temperature and working pressure had to be used for growing the Si NW's on bare SS versus on TiN. This was done to achieve roughly the same mass loading in each case.…”

“…See DOI: 10.1039/c2jm16167b a water vapour containing atmosphere. 36 Previously researchers have utilized this fact to actually create in situ conversion electrodes out of Cr 2 O 3 layers present on oxidized stainless steel according to the reaction Cr 2 O 3 + 6Li / 3Li 2 O + 2 Cr. [37][38][39] Therefore, a question remains whether lithiation/delithiation of residual oxide influences the performance of the nanowires sitting on its surface.…”

Highly Polymer‐Repellent yet Atomically Flat Surfaces Based on Organic Monolayers with a Single Fluorine Atom

“…Fouling is the accumulation of unwanted materials on solid surfaces, causing serious problems such as surface contamination, pipe blocking, metal corrosion, efficiency reduction in microfluidic devices, and so on. The fouling material can consist of either living organisms or nonliving substances, which can be of biological, inorganic chemical, or organic chemical origin .…”

Cross Sectional Examination of a Fouled Tube Removed from a Crude Oil Preheat Exchanger

“…These could result in substantial economic penalties amounting to about $12.5MM per annum for a 100,000 bbl/day refinery 1 . Such fouling concerns are as old as heat exchangers themselves and have been scrutinized from molecular to large industrial scales 2 using either empirical studies on deposit generating rigs (hot wires 3 , microbomb reactors 4,5 , batch stirred cells 6,7 and flow loops 8,9 ) or field studies on refinery preheat exchangers [10][11][12][13][14] . The studies employ two main investigation means: analysis of process data and foulant samples characterisations.…”