ISSN 2305-6894

2013, Vol. 2, Issue 4 (pp. 255–336)

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Use of a pilot scale heat exchanger-cooling tower system for the evaluation of mineral scale inhibitors

  • , and
Crystal Engineering, Growth and Design Laboratory, Department of Chemistry, University of Crete, Voutes Campus, Crete, GR-71003, Greece

Abstract: A pilot heat exchanger–cooling tower prototype was constructed and used for the evaluation of scale inhibitors in the inhibition of calcium carbonate (CaCO3) precipitation and deposition. The chemical additives that were used as inhibitors were 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC, Dequest 7000), bis(hexamethylene triaminepenta (methylenephosphonic acid)) (BHPMP, Dequest 2090) and two carboxylate-based polymers of the carboxymethyl inulin family (Dequest PB 11615 and PB 11620). The carboxylate-based polymers are “green” additives since they are environmentally-friendly, non toxic and biodegradable. Experiments were carried out in the absence of inhibitors (control) using local city water, and then in the presence of inhibitors. The inhibitors tested showed variable inhibitory activity in CaCO3 formation and deposition onto the heat exchanger. This conclusion was based on macroscopic observation (CaCO3 fouling) and on soluble Ca2+ measurements. Finally, the role of temperature of the heat exchanger, the heating time and the water flow within the unit were very important factors for CaCO3 fouling on the heated surface, considering the CaCO3 inverse solubility features.

Int. J. Corros. Scale Inhib., , 4, 255-268 PDF (1 231 K)
doi: 10.17675/2305-6894-2013-2-4-255-268

Prospects of development of a method for separate estimation of the contributions of corrosion products and inhibitor films to the total protective effect

  • R. V. Kashkovskiy
Gazprom VNIIGAZ, LLC, Razvilka, Leninsky Rayon, Moscow Region, 142717 Russian Federation

Abstract: This paper offers a modification of a method for separate estimation of the contributions of corrosion products and inhibitor films to the total protective effect. The method is based on the consideration of changes in thickness of the corrosion product film due to the inhibitor effect and film dissolution. A comparison of the original and modified methods is based on experimental results.

Int. J. Corros. Scale Inhib., , 4, 269-276 PDF (675 K)
doi: 10.17675/2305-6894-2013-2-4-269-276

Volatile inhibitors of atmospheric corrosion of ferrous and nonferrous metals. V. Study of the adsorption of inhibitors on steel from an aqueous electrolyte solution

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1 All-Russia Research Institute of Petrochemical Processes, Zheleznodorozhnyi pr. 40, St. Petersburg, 192148 Russian Federation
2 Udmurt State University, Izhevsk, Universitetskaya 1, 426034 Russian Federation

Abstract: Adsorption of ten Mannich and Schiff bases on steel from a mixed electrolyte solution (30 mg/dm3 NaCl + 50 mg/dm3 Na2SO4) was studied. The adsorption isotherms show linear segments in the medium coverage range, which may be equally attributed to both the Frumkin and Temkin isotherms. Unfortunately, experimental data are insufficient to distinguish among them. It was demonstrated that the mechanism of action of the inhibitors in vapor phase differs from that in a model electrolyte solution and that testing of volatile inhibitors in electrolytes provides no accurate pattern of corrosion inhibition in the vapor phase. The VNKh-L-21 and VNKh-L-408 inhibitors form nanoclusters that merge on the surface into a polymolecular adsorption layer.

Int. J. Corros. Scale Inhib., , 4, 277-286 PDF (547 K)
doi: 10.17675/2305-6894-2013-2-4-277-286

Laboratory assessment of the efficiency of corrosion inhibitors at oilfield pipelines of the West Siberia region V. Rotating cylinder and cage

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1 A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119071 Russian Federation
2 Open Joint Stock Company TNK-BP Management, Moscow

Abstract: This paper continues a series of publications dedicated to lab assessment of efficiency of carbon dioxide corrosion inhibitors at the oilfield pipelines of West Siberia region. It reviews the results of tests performed on “rotating cylinder” and “rotating cage” facilities. The article reviews the effect of temperature, specimen surface condition, flow velocity, presence of a hydrocarbon phase and inhibitor concentration on corrosion rate and protective properties of a wide range of commercial inhibitors. Recommendations on specific inhibitor test conditions are given to assess their applicability for protection of water lines, oil pipelines with low watercut and oil pipelines with high product watercut.

Int. J. Corros. Scale Inhib., , 4, 287–303 PDF (1 299 K)
doi: 10.17675/2305-6894-2013-2-4-287-303

Application of SSRT to estimate the effect of corrosive medium on the liability of X70 pipe steel to stress corrosion cracking

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1 A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119071 Russian Federation
2 Open Joint-Stock Company “Gazprom”, ul. Nametkina 16, Moscow, 117997 Russian Federation

Abstract: The slow strain rate test was used to study the effect of a number of corrosive soil electrolyte components and corrosion inhibitors on the liability of pipe steel X70 to stress corrosion cracking in weakly acidic and neutral media simulating the electrolyte under delaminated coatings on underground pipelines. The electrochemical behavior of X70 pipe steel in the presence of some corrosion inhibitors was studied. It was shown that inhibitors of metal anodic dissolution can considerably improve the cracking resistance of pipe steel.

Int. J. Corros. Scale Inhib., , 4, 318 – 336 PDF (1 461 K)
doi: 10.17675/2305-6894-2013-2-4-318-336

Effect of veratric acid and 3,4-dimethylphenyl-anthranilic acid on the corrosion and electrochemical behavior of cadmium, bismuth, and their alloy in a borate solution

  • , , and
Southern Federal University, ul. Zorge 7, Rostov-on-Don, 344090 Russian Federation

Abstract: The corrosion and electrochemical behavior of cadmium, bismuth, and a cadmium-bismuth alloy containing 50 wt.% of cadmium, in pure borate neutral solution and with addition of veratric and 3,4-dimethylphenylanthranilic acids is compared. It is shown that veratric acid has a more significant effect on the corrosion and anodic dissolution of the metals, whereas 3,4-dimethylphenylanthranilic acid more strongly affects the alloy behavior.

Int. J. Corros. Scale Inhib., , 4, 311–317 PDF (563 K)
doi: 10.17675/2305-6894-2013-2-4-311-317

Peculiarities of protective efficiency of nitrogen containing inhibitors of steel corrosion

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1 Department of Analytical Chemistry, Derzhavin State University, Tambov, 392000 Russian Federation
2 Department of Chemistry, Tambov State Technical University, Tambov, 392000 Russian Federation

Abstract: The protective efficiency of a number of nitrogen containing inhibitors against steel hydrosulfide corrosion and their effect on the kinetics of partial electrode reactions have been studied by gravimetrical corrosion tests, polarization resistance and impedance spectroscopy methods. The bactericidal efficiency of the inhibitors with respect to sulfate reducing bacteria (SRB) has been estimated as a function of their nature and concentration.

Int. J. Corros. Scale Inhib., , 4, 304–310 PDF (551 K)
doi: 10.17675/2305-6894-2013-2-4-304-310

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