Design of self-heating test platform for sulfide corrosion and oxidation based on Fuzzy PID temperature control system

In this paper, the changes of oxidation temperature of sulfide corrosion and the deficiency of distributed optical fiber application were analyzed. The test platform of oxidation temperature of sulfide corrosion was established, and the performance test of optical fiber and the simulation of oxidation temperature of sulfide corrosion were realized. The hardware part of the control system used STM32 as the controller, the software part was based on the process characteristics of the controlled object, using MATLAB to carry out the simulation of PID, fuzzy, fuzzy PD plus I, fuzzy PID algorithms, and their performance are evaluated using both single indexes and comprehensive indexes. The experimental results also showed that the proposed fuzzy PID can achieve better control performance with less overshoot and shorter setting time. Therefore, the fuzzy PID was chosen as the temperature control algorithm to build the optical fiber sensor test platform, and an alarm method for testing the oxidation temperature of large area sulfide corrosion based on the optical fiber performance was obtained. Then, considering the influence of spatial resolution on optical fiber sensor, this paper used piecewise PID to simulate the temperature rise process of three stages of sulfurization corrosion and oxidation. The results showed that the alarm method of oxidation temperature of sulfurization corrosion has limitations for small-scale oxidation of sulfurization corrosion, and it needed to be combined with machine learning to identify temperature anomaly.

Influence of Structural Heterogeneity of High-Strength OCTG Tubes on Sulfide Corrosion Cracking Resistance

High-strength oil country tubular goods (OCTG) like C110, according to standard API 5CT (yield strength at least 758 MPa), are subject to requirements in terms of mechanical and corrosion properties. In this work, we studied the influence of seamless tubes microstructure with a 177.8 mm diameter and 10.36 mm wall thickness of class С110 high-strength steel to sulfide stress corrosion cracking (SSC) and sulfide stress corrosion cracking with low strain rates (SSRT). Tubes were obtained from continuous billets by screw piercing with preliminary quenching and tempering. It was established that cracking during the tests always begins from the inner surface of the tube. Rough segregation bands were found on the inner tube surface, which occupies about a third of the thickness. It is shown that the SSRT assessment technique allows to estimate the threshold value of the resistance.

Analysis of adsorption of carbon steel corrosion inhibitor in model stratum waters by polylogarithmic isotherm

Using the methods of gravimetry, potentiodynamic polarization, and impedance spectroscopy, the protective effectiveness of the inhibitory composition INCORGAZ-111 with respect to hydrogen sulfide corrosion of carbon steel St3 in NACE and Samotlor oil field model stratum waters has been studied. Surface coverage is determined on the basis of the electric double layer capacity in presence of the inhibitor. Its adsorption is interpreted using the polylogarithmic isotherm with a big energy gradient of adsorption centers, that indicates linear energy heterogeneity of the surface. The constants of adsorption equilibrium, the energy gradient and the energy dispersion of adsorption centers as well as adsorption free energy were calculated.

Chemical Removal of Lead Corrosion Products

Restoration treatment, specimen preparation or mass loss measurements on coupons made of lead require a reliable process of dissolution of corrosion products. In this study, several types of model corrosion products with compositions representative of those found on real objects were prepared and characterized. Ten solutions were then thoroughly tested in interval cleaning experiments, regarding the efficiency of removal of the corrosion products, corrosivity towards bare lead, and remnants left on the surface. The solution recommended in the current version of the ISO 8470 standard was found to be improper for the cleaning of both historical artefacts and corrosion coupons due to its inability to remove sulfide corrosion products and the risk of surface contamination and staining. A solution of 20% hydrochloric acid is the best choice for the preparation of lead coupons before exposure or for evaluation of mass loss of exposed samples because its somewhat higher corrosivity towards metallic lead is tolerable for these applications. Rochelle salt solution was found to be optimal for the cleaning of historical artefacts free of sulfide corrosion products due to the lowest corrosivity. None of these alternative solutions leave remnants on the surface and they are efficient at laboratory temperature.

Removing of sulfide corrosion layers by an arc plasma process

In this paper, the removal of the sulfide layer formed on an FV(520)B stainless steel in the simulated environment of air compressor blade service conditions in a reaction kettle by arc plasma was investigated to explore the mechanism and technology of the sulfide layer removed by arc plasma from a blade surface. The sulfide lattice energy is studied by using the Born Haber cycle. Besides, the energy balance of the removal process is calculated. The treated surface morphology of samples was analyzed by scanning electron microscopy and energy dispersive spectrometer. The results indicate that the energy of the arc spot is enough to evaporate the sulfide film. Due to the different electronic work functions, an arc spot is first formed on the sulfide film, and then the voltage signal is segmented during the removal process. The voltage signal in the removal process can remove sulfide without harming the metal matrix. Besides, the increase in current can improve the removal efficiency and the surface roughness of the sample. It can be revealed, by analyzing the surface composition of samples with different currents, that the sulfur content is very low, indicating that it is feasible to remove the sulfide layer by arc spot plasma.

Obtaining and investigation of the salts of cis – (2-((1h-benzo [d][1,2,3] triazol-1-yl) methyl) -1,3-dioxolan-4-yl) methyl benzoate with acetic and hydrochloric acid

New biocides (I and II) were synthesized against corrosive bacteria as a result of the reaction of cis–(2-((1H-benzo[d][1,2,3]triazol-1-yl)methyl)-1,3-dioxalan-4-yl) methyl benzoate based on benzotriazole with acetic and hydrochloric acid. Their physical-chemical properties were investigated and biocidal properties studied in various concentrations, as well as the effect of reagents on hydrogen sulfide corrosion. It was specified that the protective effect of the synthesized salts from hydrogen sulfide corrosion was 75 %, and the biocidal effect from microbiological corrosion was equal to 100 %.

Grip of Mature and Fresh Concrete with Heat Treatment in Winter Conditions

Port infrastructure facilities, located in cold climatic zones in contact with sea water, are destroyed due to carbonation of concrete and sulfide corrosion. The restoration of the reinforcement protective layer by standard methods does not provide high-quality grip of the concrete structures that has undergone destruction and the repair concrete. The study of the “old” and “new” concrete grip using forced heating of the “new” one shows that mixing water with cement clinker components dissolved in it penetrates through the pores and capillaries deep into the “old” concrete to a depth of 60–70 mm under the temperature factor influence. After hardened concrete got its standard strength, it exceeds concrete grip, hardened under normal conditions by 30%.