Polymer compatibilty with key infrastructure elastomers and plastics was determined using a neat bio-oil that was derived via fast-pyrolysis of woody biomass. The elastomers were exposed to the bio-oil in a sealed container for 4 weeks while the plastics were exposed for 16 weeks. The bio-oil was kept at ambient temperatures (approximately 20C) and atmopsheric pressures.The mass volume change and hardness were measured and compared to the original starting values. These results were compared to identical specimens exposed to neat diesel fuel for baseline comparison. The results provide a useful comparison of assessing bio-oil compatibilty with existing infrastructure materials.

Stabilized austenitic stainless steel (SS) grade 347 is used extensively in high-temperature processes in the petroleum refining industry, while duplex SS (DSS) grade 2205 is a relatively newer material in the industry. Though these grades of SSs perform well in refinery process streams, there are incidents of failure of process equipment attributable to stress corrosion cracking (SCC).  The paper deals with a study on the cracking susceptibility of SS grade 347 and DSS grade 2205 in refinery simulated process environments containing hydrogen sulfide and chloride.  The paper also reports the electrochemical behavior of these SSs in the medium containing hydrogen sulfide and chloride.  The electrochemical behavior of the alloys was assessed by cyclic polarization experiments.  Slow strain rate test (SSRT) was used to evaluate the susceptibility of the alloys to SCC. The cyclic polarization studies indicate that the H2S – chloride synergism had a pronounced effect on the localized corrosion susceptibility of 347 SS, while the effect was marginal on the alloy DSS 2205. The SCC susceptibility of 347 SS and DSS 2205 is strongly influenced by hydrogen sulfide-chloride synergism.  Initiation of corrosion pits and the sulfidation of active pits due to the synergism were the important steps in the initiation of SCC.   

There are three known types of high temperature sulfidation present in the refining industry. Two of them have industry recognized methodologies for damage prediction, and they both manifest as general thinning morphologies. They are known as H2-free sulfidation and H2/H2S corrosion. The third type, although recognized as H2-free, low-sulfur corrosion, does not have an accepted chemical theory or a prediction tool, and it manifests as a localized thinning morphology. This third type of sulfidation is much less common and occurs in units and process conditions where little-to-no H2S would be expected to be present. This paper discusses the operating conditions in two known damage cases presented here and provides a viable chemical theory that could lead to the observed damage profile. In addition, an approach to mitigation of this attack is discussed.