Effect of CO2 Partial Pressure on CO2/H2S Corrosion of Oil Tube Steels

2014 ◽  
Vol 962-965 ◽  
pp. 407-410
Author(s):  
Ying Wang

The CO2/H2S corrosion behaviors of oil tube steels N80 and P110 at different CO2 partial pressure (45psi, 135psi, 225psi, 315psi) were investigated by corrosion tests, corrosion rate calculation and corrosion morphology observation. The results show that at different CO2 partial pressure, super-serious CO2/H2S corrosion occurs on steel N80 and steel P110. With the increase of CO2 partial pressure, the CO2/H2S corrosion rates of both steels increase gradually.

2011 ◽  
Vol 239-242 ◽  
pp. 3131-3134
Author(s):  
Ying Wang ◽  
Ping Li

The CO2/H2S corrosion behaviors of oil tube steels N80 and P110 at different H2S partial pressure (0.2psi, 3psi, 9psi, 18psi) were investigated by autoclave corrosion tests, corrosion rate calculation and corrosion morphology observation. The results show that with the increase of H2S partial pressure the CO2/H2S corrosion rates of both steels increase at first and then decrease after the peaks appear at 3psi H2S.


2014 ◽  
Vol 908 ◽  
pp. 111-114 ◽  
Author(s):  
Ying Wang

The CO2/H2S corrosion behaviors of oil tube steels N80 and P110 at different temperature were investigated by corrosion rate calculation and corrosion morphology observation. The results show that with the increase of temperature, the CO2/H2S corrosion rates of both steels increase at first and then decrease, and reach the peak at 90°C. The corrosion rate of steel P110 is higher than that of steel N80.


2013 ◽  
Vol 816-817 ◽  
pp. 1243-1249
Author(s):  
Chong Sun ◽  
Jian Bo Sun ◽  
Yong Wan ◽  
Xin Su ◽  
Yong Zhang

Influences of temperature and CO2 partial pressure on CO2 corrosion behaviors of 25CrMnVA steel were investigated in the simulated oil field environments. The corrosion rates were measured under high temperature and high pressure condition. SEM, EDS and XRD were used to analyze the morphologies and characteristics of corrosion scales on the steels. The results shows that the corrosion rates of 25CrMnVA steel change little below 65°C, the corrosion feature is uniform corrosion. The corrosion rates increase rapidly after 65°C, mesa corrosion is found on the surface of steel. The corrosion rates decrease firstly and increase subsequently with the rising of CO2 partial pressure, and the minimal corrosion rate presents near CO2 critical pressure. The compactness of corrosion scale improves with the increase of CO2 partial pressure below 8MPa, which causes uniform corrosion rate reduced. Under supercritical CO2 condition, the local defects in the surface of corrosion scale increase, and the compactness of corrosion scale reduces,which cause the increase of corrosion rate sharply. The corrosion rate and corrosion morphology are closely related to the state of corrosion scale.


2014 ◽  
Vol 1665 ◽  
pp. 195-202 ◽  
Author(s):  
Osamu Kato ◽  
Hiromi Tanabe ◽  
Tomofumi Sakuragi ◽  
Tsutomu Nishimura ◽  
Tsuyoshi Tateishi

ABSTRACTCorrosion behavior is a key issue in the assessment of disposal performance for activated waste such as spent fuel assemblies (i.e., hulls and end-pieces) because corrosion is expected to initiate radionuclide (e.g., C-14) leaching from such waste. Because the anticipated corrosion rate is extremely low, understanding and modeling Zircaloy (Zry) corrosion behavior under geological disposal conditions is important in predicting very long-term corrosion. Corrosion models applicable in the higher temperature ranges of nuclear reactors have been proposed based on considerable testing in the 523−633 K temperature range.In this study, corrosion tests were carried out to confirm the applicability of such existing models to the low temperature range of geological disposal, and to examine the influence of material, environmental, and other factors on corrosion rates under geological disposal conditions. A characterization analysis of the generated oxide film was also performed.To confirm applicability, the corrosion rate of Zry-4 in pure water with a temperature change from 303 K to 433 K was obtained using a hydrogen measuring technique, giving a corrosion rate for 180 days of 8 × 10-3 μm/y at 303 K.To investigate the influence of various factors, corrosion tests were carried out. The corrosion rates for Zry-2 and Zry-4 were almost same, and increased with a temperature increase from 303 K to 353 K. The influence of pH (12.5) compared with pure water was about 1.4 at 180 days at 303 K.


2014 ◽  
Vol 900 ◽  
pp. 39-42
Author(s):  
Quan Tong Jiang ◽  
Xing Gang Li ◽  
Yong Jun Li ◽  
Ming Long Ma ◽  
Guo Liang Shi ◽  
...  

The corrosion behaviors of peak-aged Mg-7Gd-5Y-1Nd-0.5Zr alloys in CO2atmosphere under different relative humidity were investigated by OM, SEM. The weight loss rates, corrosion morphology and residual mechanical properties were also analyzed. The corrosion rates of specimens in CO2atmosphere at 70% relative humidity were highest than others. Relevancy of the influence factors included relative humidity and concentration of CO2were researched. The results show that relative humidity and concentration of CO2in the environment both played an important role in corrosion behaviors.


2019 ◽  
Vol 66 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Jun Wang ◽  
Zili Li ◽  
Gan Cui ◽  
JianGuo Liu ◽  
Chuanping Kong ◽  
...  

Purpose The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution. Design/methodology/approach The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy. Findings The results showed that E-I polarization curves under 200-1,200 A/m2 interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution. Originality/value All tests were conducted at a relative higher DC density (200-1,200 A/m2). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.


2013 ◽  
Vol 438-439 ◽  
pp. 353-356
Author(s):  
Ping Li ◽  
Ying Wang

The corrosion behavior of rebar HRB400 in 0.5 wt.%, 1.5 wt.% and 3.5 wt.% NaCl solutions was investigated by corrosion rate calculation and corrosion morphology observation. The results showed that, with the increase of corrosion time from 240h to 720h, the corrosion rate of rebar HRB400 in each NaCl solution increases. With the increase of NaCl solution concentration, the corrosion rate of rebar HRB400 increases. The corrosion morphologies show strong consistency with the test results of corrosion rate.


Author(s):  
J. Raghu Shant ◽  
Richard Barker ◽  
Anne Neville

The inner surface of pipe plays a crucial role in top of line corrosion when condensation of droplet takes place. Condensation over inner periphery of pipeline takes place by droplet formation due to differential temperature inside the pipe and external environmental factors. To understand the change in corrosion rates with respect to droplet flow and temperature [40°C, 60°C and 80°C], a rig with curvature 80mm which simulates top of line corrosion is designed to carry out experiments at 0°, 15° and 30° inclinations in fixed 3 litre beaker. Droplet formation on the sample as well as on perpex surface has been captured at different temperatures to understand the droplet size formation. Corrosion rate calculation is done my weight loss methods which are generally preferred in on site analysis instead of electrochemical measurements. Surface analysis is carried out with the help of optical microscope and optical profilometer where corrosion rate, inclination were correlated to average surface roughness.


1986 ◽  
Vol 84 ◽  
Author(s):  
M.D. Merz ◽  
F. Gerber ◽  
R. Wang

AbstractThe Materials Characterization Center (MCC) at Pacific Northwest Lab- oratory is performing three kinds of corrosion tests for the Basalt Waste Isolation Project (BWIP) to establish the interlaboratory reproducibility and uncertainty of corrosion rates of container materials for high-level nuclear waste. The three types of corrosion tests were selected to address two distinct conditions that are expected in a repository constructed in basalt. An air/steam test is designed to address corrosion during the operational period and static pressure vessel and flowby tests are designed to address corrosion under conditions that bound the condi ring the post-closure period of the repository.The results of tests at reference testing conditions, which were defined to facilitate interlaboratory comparison of data, are presented. Data are reported for the BWIP/MCC-105.5 Air/Steam Test, BWIP/MCC-105.1 Static Pressure Vessel, and BWIP/MC-105.4 Flowby Test. In those cases where data are available from a second laboratory, a statistical analysis of interlaboratory results is reported and expected confidence intervals for mean corrosion rates are given. Other statistical treatment of data include analyses of the effects of vessel-to-vessel variations, test capsule variations for the flowby test, and oven-to-oven variations for air/steam tests.


2020 ◽  
Vol 39 (1) ◽  
pp. 340-350
Author(s):  
Mingjing Wang ◽  
Song Zeng ◽  
Huihui Zhang ◽  
Ming Zhu ◽  
Chengxin Lei ◽  
...  

AbstractCorrosion behaviors of 316 stainless steel (316 ss) and Inconel 625 alloy in molten NaCl–KCl–ZnCl2 at 700°C and 900°C were investigated by immersion tests and electrochemical methods, including potentiodynamic polarization and electrochemical impedance spectroscopy. X-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy were used to analyze the phases and microstructures of the corrosion products. Inconel 625 alloy and 316 ss exhibited high corrosion rates in molten chlorides, and the corrosion rates of these two alloys accelerated when the temperature increased from 700°C to 900°C. The results of the electrochemical tests showed that both alloys exhibited active corrosion in chloride molten salt, and the current density of 316 ss in chloride molten salt at 700°C was 2.756 mA/cm−2, which is about three times the value for Inconel 625 alloy; and the values of the charge transfer resistance (Rt) for Inconel 625 were larger than those for 316 ss. The corrosion of these two alloys is owing to the preferred oxidation of Cr in chloride molten salt, and the corrosion layer was mainly ZnCr2O4 which was loose and porous and showed poor adherence to metal.


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