Experimental substantiation of the corrosion rate of pipe steel

Определяющее значение в развитии дефектности металла труб имеет коррозионный фактор, а также деградация механических свойств трубных сталей в процессе эксплуатации трубопроводов. Авторами приведены результаты экспериментальных исследований по оценке скорости коррозии и склонности к трещинообразованию трубных сталей, наиболее распространенных на длительно эксплуатируемых магистральных нефте- и нефтепродуктопроводах. Разработана методика определения количественных показателей коррозионно значимых параметров для обоснования вывода в капитальный ремонт трубопроводов на основе результатов натурных экспериментальных исследований скорости коррозии фрагментов трубной стали при различных условиях поляризации и коррозионной активности грунта. Объект исследования - фрагменты труб (пластины) 50×50×3 мм, изготовленные из стали марок 09Г2С и 17Г1С. Полученные результаты позволили сформулировать рекомендации по уточнению количественных критериев коррозионно значимых факторов для обоснования вывода трубопровода в капитальный ремонт: 1) необходимо учитывать марку трубной стали (установлено, что сталь 17Г1С на 20-30 % более устойчива к коррозии, чем сталь 09Г2С, особенно в части образования локальных повреждений - язв и питтингов); 2) при значениях удельного электрического сопротивления грунта менее 20 Ом⋅м скорость коррозии возрастает примерно на порядок независимо от марки стали и наличия системы электрохимической защиты. This work presents the results of experimental studies on the assessment of the corrosion rate and the cracking tendencies of pipe steels, most common in the main oil and oil product pipelines that have been used for a significant amount of time. A methodology was developed for determining quantitative indicators of corrosion-significant parameters to justify the overhaul of main pipelines based on the results of field experimental studies of the corrosion rate of pipe steel fragments under various conditions of polarization and corrosive activity of the soil. The object of the study is pipe fragments (plates) with the dimensions of 50×50×3 mm, made of steel with the grades 09G2S and 17G1S. The results made it possible to formulate recommendations for refining the quantitative criteria of corrosion-significant factors to justify the overhaul of the pipeline: 1) it is necessary to take into account the pipe steel grade (it was found that 17G1S steel is 20-30 % more resistant to corrosion than 09G2S steel, especially in the formation of local damages - corrosion pits and pittings); 2) at values of specific soil resistance less than 20 Ohm⋅m, corrosion rate increases by about an order, regardless of the steel grade and the usage of an electrochemical protection system.

The series of measures for improvement of safety in oil and gas facilities producing, processing and transporting materials containing hydrogen sulfide Part 1. Corrosion-mechanical attack of hydrogen sulfide-containing media on steel equipment. The choice of construction steels and noncorrosive alloys for the oil and gas equipment

The necessity of the complex approach is defined for increase of reliability of the oil and gas equipment operated under pressure of hydrogen sulfide-containing medium, including: - control at the stages of design, manufacturing, commissioning, operation, repair and reconstruction; - organization of corrosion service; - rational choice of materials for equipment manufacturing and its repair; - use of different methods to protect equipment against corrosion: - diagnostics of equipment and evaluation of corrosion protection efficiency; - conducting corrosion tests of materials and corrosion control. The trend of increasing corrosive activity of the products of a number of hydrogen sulfide-bearing oil and gas fields is described. This is associated with their watering and contamination by sulfate-reducing bacteria. All types of corrosion-mechanical damage of steels in accordance with GOST R 53679-2009 (ISO 15156-1:2001) are considered. Comments are given on each of these types of damage and the types of steels that are prone to these defects are shown. The recommendations of GOST R 53679-2009 (ISO 15156-1:2001) are given for the selection of steel equipment operated under pressure of hydrogen sulfide-containing media depending on the type of their corrosionmechanical failure, with comments. Requirements for the use of steels modified with rare-earth metals (REM) and alkaline-earth elements (ALE) intended for operation in hydrogen sulfide-containing media are given.

COMPOSITION FOR PROTECTING TECHNOLOGICAL EQUIPMENT AGAINST SALT DEPOSITS AND INTERNAL CORROSION

Aimed studies on the synthesis of metal complexonates have carried out. The reaction of obtaining zincate zincate oxyethylene diphosphonic acid OEDP has studied. On the basis of synthesized zincate-OEDP, compositions of corrosion inhibitors and deposits of mineral salts with the addition of a vacuum residue of monoethanolamine (RMEA) and polyaminocrotanol (PKI-3), which are able to effectively suppress corrosion processes in environments with different initial corrosive activity, have been compiled. It is proved that the high efficiency of the composition OEDP : zincate-OEDP : PKI-3 (maximum protective effect - 97.9%) is much more effective than the composition OEDP : zincate-OEDP : RMEA (maximum protective effect - 92.0%). This is due to an increase in ammonium centers, the strength of complexonates based on OEDP, and the presence of a strong methyl-nitrogen bond in the compositions prepared with PKI-3, as a result of which stronger protective layers are formed on the surface of the metal subject to corrosion. Low-stage, energy-saving technologies for the production of inhibitors of mineral salt deposition and corrosion based on local raw materials and secondary industrial products have developed.

Study of the orthopolyphosphate specimen "SeaQuest Liquid" for anticorrosion and stabilization water treatment

Most water supply systems operating in Ukraine are made of steel or cast iron, which are subject to corrosion. The Institute of Water Problems and Land Reclamation of the National Academy of Sciences of Ukraine carried out the experimental studies on the effect of an orthophosphate corrosion inhibitor on the quality of drinking water and the rate of corrosion as a result of its appliance in various doses in the water supply network. The water supply system of Obolon district of the city of Kiev was selected as the object of research. A characteristic feature of this water supply system is the use of various sources of water supply - groundwater and surface waters of the Desna and Dnieper rivers. The results of the calculation of water corrosivity carried out at the Institute based on the chemical analysis of the quality of water taken from 29 wells at the research object showed that the Langelier indices obtained using the calculation formulas for all sampling points are in the range from 0,89 to 1,77, which indicates the continuous and significant corrosive activity of water at all sampling point. The Risner index in all samples was in the range from 7.8 to 8.8, which indicates the significant pipeline corrosion. That is especially typical for the water from the well № 232, the Rizner index of which is 9.58, which indicates very intensive corrosion of the pipeline. Indicators rH2, for all samples, calculated both by F.U. Clarke and by the formula of A.I. Trufanov, indicate that the studied aquatic environment is very favorable for the vital activity of iron bacteria in general, and the pH - Eh zone of water samples indicates that there is an active vital activity of various strains: Leptothrix, Gallionella , Thiobacillus thiooxcidans or their combined activity. All the studied factors indicate that the most likely there is a complex genesis of corrosion processes in water supply networks, which combines both physicochemical and biological processes. This combination usually contributes to the processes of active secondary water pollution by the products of pipeline corrosion. Indicators rH2, for all samples, calculated by the formulas of F.U. Clark and of A.I. Trufanov, indicate that the studied aquatic environment is very favorable for the activity of iron bacteria in general, and the pH - Eh zone of water samples indicates that there is a rather high activity of different strains: Leptothrix, Gallionella, Thiobacillus thiooxcidans or their combined activity. The results of the research showed that for all ways to use of "SeaQuest Liquid" spicemen in the water of all sampling points there were no deviations from the standards of basic physicochemical parameters: the average pH of water was 7,67 ± 0.01, total water hardness was 4,3 ± 0,03, total alkalinity - 4,4 ± 0,05 mmol/dm,3 calcium content - 58,6 ± 0,7 mg/dm3, magnesium - 16,1 ± 0.2 mg/dm3, hydrocarbons - 261,4 ± 4,8 mg/dm3, manganese <0,01 mg/dm3, sulfates - 21,9 ± 1,2 mg/dm3, chlorides - 44,3 ± 1,4 mg/dm3, sodium and potassium - 44,0 ± 2,0 mg/dm3, residual chlorine - 0,35 ± 0,02 mg/dm3, ammonium - 0,2 ± 0.01 mg/dm3, permanganate oxidation - 2,3 ± 0,1 mgО2/dm3, nitrites - 0,09 ± 0,01 mg/dm3, nitrates - 1,53 ± 0,14 mg/dm3, total mineralization - 459,9 ± 15,1 mg/dm3. In some samples of water treated with “SeaQuest Liquid”, the iron content exceeded the hygienic standard (0,2 mg/dm3) and exceeded the maximum allowable level (1,0 mg/dm3). In drinking water samples, the levels of substances that are the part of "SeaQuest Liquid" specimen (polyphosphates, orthophosphates), varied at different sampling points but were within the normative values. The anticipated biological component of corrosion according to the calculated Rh2 index, was confirmed. In the presence of sulfate-reducing and thiobacteria in water, "SeaQuest Liquid" specimen increases the corrosion rate of steel by 2,9-7,2 times; subject to additional disinfection of water when treating with sodium hypochlorite, it reduces this indicator by 1,4-2,7 times. Under the action of "SeaQuest Liquid" in water treated with sodium hypochlorite, there was a decrease in the Langelier index: from -2,23 to -2,08 and from -1,79 to -1,70, indicating a decrease in its corrosive activity. In water untreated with sodium hypochlorite under the action of "SeaQuest Liquid" there was some increase in the Langelier index: from -1.80 to -1,95 and from -1,85 to -2,78; from -2,01 to -2,13, which indicates an increase in its corrosive aggressiveness.

The Use of Phosphate Compositions for Chemical Treatment of Make-Up Water in Centralized Heat Supply Systems

The paper investigates two different protective phosphate compositions for the chemical treatment of water and the use of them with a view to improve quality of “make-up” water in water heating systems. The research proved a positive effect of reducing the corrosive activity of water and the amount of scale.

Reduction of corrosive activity of operating oil in the benzene department Coke Production of PJSC «ArcelorMittal Kryvyi Rih».

REDUCTION OF CORROSIVE ACTIVITY OF OPERATING OIL IN THE BENZENE DEPARTMENT OF COKE PRODUCTION OF PJSC «ARCELORMITTAL KRYVYI RIH» © I.I. Sikan, R.V. Karenov, N.V. Mukina, S.N. Solonko (Coke production of PJSC «ArcelorMittal Kryvyi Rih», 50095, Dnipropetrovsk region, Kryvyi Rih, Kryvorizhstal str., 1, Ukraine), L.P. Bannikov, PhD in technical sciences (State Enterprise "Ukrainian State Research Coal Chemical Institute (UHIN)", 61023, Kharkov, Vesnina st., 7, Ukraine) This paper analyzes and formulates the optimal technological solutions to reduce the corrosiveness of the absorption oil. The problem of reducing the corrosiveness and the ability of the absorbing oil to form the precipitates becomes especially actual in view of the introduction in the technological scheme of a new tube furnace ThyssenKrupp (Germany) for heating the absorption oil in the benzene section. All major work has now been completed at this facility, and soon the new furnace will be commissioned, which should significantly improve the regeneration of the absorption oil. Research of quality indicators of fresh oil and potentiodynamic testing of its water extracts has been fulfilled. To verify that the tube furnace tube material meets the requirements, a spectral analysis of a sample of the damaged tube was performed. The suspended solids of the circulating oil were observed under a microscope at a magnification of ×250. It was revealed that recycled absorption oil can lose quality as a result of tube furnace wear, frequent stoppages for repairs and watering of oil with coke oven gas condensate in scrubbers. Exit from the state of watering occurs during the operation of the distillation department due to "steaming" in the column. As a result, the concentration of salts in the oil occurs and, as a result, its corrosiveness increases. Oil watering in the distillation column occurs when the heating temperature drops. Before starting a new tube furnace, it is advisable to renew the entire working volume with fresh oil with preliminary flushing of the equipment. This will make it possible not to water it in the future during the smooth operation of the distillation and to maintain the proper quality of the absorption oil. Keywords: capture of benzene hydrocarbons, absorbing oil, distillation column, regeneration, tubular furnace, corrosiveness, survey, watering, suspended particles, aggregation. Corresponding author I.I. Sikan, е-mail: [email protected]

Upgrading the hot water supply system as a way to save energy

The efficiency of works on replacement of steel pipelines of hot water supply of Kazan with pipes from polymer materials was considered. Due to the high corrosive activity of water, the service life of hot water pipelines does not exceed 8-10 years. To improve the reliability and quality of the supply of hot water to consumers, the possibility of modernizing hot water supply networks using pipelines made of polymer materials is being considered. The problem of physical wear of heat supply networks is disclosed; analysis of polymer pipelines use for energy saving purposes is carried out. Thermal energy savings are calculated after the modernization of heating networks. The costs, savings and payback period of the energy-saving measures are determined.

Synthesis, Anti-microbial, Flameretardance and Anti-corrosive Activity of Some New Heterocycles Incorporating Coumarin moiety

In the present study a series of novel heterocyclic compounds (2-16) incorporating coumarin moiety was synthesized. The newly synthesized compounds were elucidated on the basis of elemental analysis, spectral data, were tested for in-vitro antibacterial activity against Staphylococcus aureus, Bacillus subtilis (Gram-positive bacteria), Salmonella typhimurium, Escherichia coli (Gram-negative bacteria) and Candida albicans, Aspergillus fumigatus (fungi). Coumarin derivatives (1,6,16) were chosen to evaluate the anti-corrosion, flame retardant properties. The results clearly showed that, the incorporation of coumarin derivatives into epoxy coating have led to improve the flame residency, corrosion resistance, and mechanical properties of investigated coating and confirmed that these new developed varnishes have an excellent properties as flame resistance and anticorrosive for mild steel.