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Haifa, Israel

Groysman A.,Oil Refineries Ltd. | Groysman A.,ORT Braude College | Simon R.,Oil Refineries Ltd. | Feldman B.,IKA Laboratories | And 2 more authors.
European Corrosion Congress 2010 - EUROCORR 2010 | Year: 2010

The aim of this work is to analyse hydrogen damage, monitoring, and possible prevention at the oil refineries' units. Hydrogen gas occupies an essential place in the processes in the oil refining industry: hydrodesulfurizers, hydrocrackers, and catalytic reformers. In addition to these processes, there are some sources of hydrogen gas arising from corrosion of carbon steel equipment in contact with aqueous solutions of acids, such as H 2S (sour water), HC1, HCN, H 2SO 4, and HF. High temperature chemical attack of carbon steel equipment by naphthenic and other organic acids can be related to hydrogen damages owing to appearing of hydrogen gas on metal surface as a result of such attack. Historically many names of hydrogen damages appeared: hydrogen degradation, hydrogen embrittlement, hydrogen blistering, decarburization, hydrogen stress cracking (HSC), hydrogen attack, high temperature hydrogen attack (HTHA), hydrogen-induced cracking (HIC), also known as stepwise cracking (SWC), stress-oriented hydrogen-induced cracking (SOHIC), sulfide stress cracking (SSC). This profusion of names does not always correctly elucidate and explain them, and can even confuse and complicate their detection, understanding, monitoring, and control. From analyzing the literature on this subject and based on our own experience, we differentiate all hydrogen damage failures into two main groups based on two mechanisms: electrochemical processes (mainly at low temperature, up to ~100°C) arising from acid corrosion and cathodic protection, and high temperature (between 200 and 900°C) arising from the presence of hydrogen gas at high pressures. Examples of hydrogen damage are given for the various units of oil refineries. Different monitoring methods were developed for detection of possible hydrogen damages. Hydrogen can be detected either in intrusive or non-intrusive devices called hydrogen probes. Hydrogen that penetrates through a metallic wall can be detected with manometric (hydrogen pressure,) or vacuum method, electrolytically (hydrogen ionization from H atoms into H + ions), heat conduction (gas chromatography), vacuum extraction at 400°C, or hydrogen effusion. Monitoring methods are critically reviewed. Preventive measures of hydrogen failures are differentiated into two groups according to low (electrochemical) and high temperature (dissociation of hydrogen molecules) mechanisms. The first group includes protective measures from hydrogen blistering and sulfide stress cracking (SSC): metallurgical measures, change of environmental conditions (removing aggressive species such as sulfides, cyanides, and arsenic compounds, neutralization, injection of inhibitors of hydrogen penetration), use of organic, inorganic, and metallic coatings, heat treatment and proper welding. The second group includes metallurgical measures (use of steels containing chromium and molybdenum, and decrease of carbon content in steel), heat treatment, and proper welding. Analysis of preventive measures of hydrogen failures was carried out and recommendations were given. Examples of hydrogen damages are given for the isomerization and hydrodesulfurizer units of oil refinery. Source

Groysman A.,Oil Refineries Ltd. | Siso R.,Oil Refineries Ltd. | Siso R.,ORT Braude College
European Corrosion Congress 2011, EUROCORR 2011 | Year: 2011

The aboveground storage tanks (AST) at some oil refineries are in use above 50 years. Most AST containing different fuels (gasoline, kerosene, diesel oil and fuel oil) are made of carbon steel. Gasoline and kerosene tanks are furnished with floating roofs and pontoons made of carbon steel for decrease of vaporization of light fractions of hydrocarbons. Diesel oil and fuel oil tanks are equipped with fixed roofs. Corrosion mechanism and preventive measures of corrosion control of inner surfaces of AST containing different fuels are analyzed in [1-3]. The aim of this work was the calculation of corrosion rates of carbon steel shells (courses), roofs and floors of AST containing different fuels after 62-67 years of service. Outer surfaces of tanks are painted. Inner surfaces of tanks usually are not painted. Therefore corrosion occurs on inner surfaces of AST. Thicknesses of different parts of AST containing various fuels were measured and corrosion rates were calculated. These thicknesses and corrosion rates were compared with allowable minimum thicknesses and allowable maximum corrosion rates for AST. Thus, these measurements allowed deciding about the remaining life of AST, which parts of tanks should be repaired or changed, about corrosiveness of different fuels in tanks during their storage, and how often we should measure thicknesses of tanks' material. Anti-corrosion preventive measures are given at the end of this work. Source

Meth S.,Bar - Ilan University | Meth S.,University of Southern California | Savchenko N.,Oil Refineries Ltd. | Koltypin M.,Bar - Ilan University | And 4 more authors.
Corrosion Science | Year: 2010

Thioacetate hexadecyltrimethoxysilane was deposited on SiO2-coated stainless steel to form a thioacetate-functionalized monolayer. In situ oxidation of the thioacetate yielded a sulfonate-functionalized monolayer. Solution deposition of TiO2 on this monolayer covered the stainless steel with a thin layer of the metal oxide (5-10 nm). Cyclic voltammetry (CV) and potentiostatic current transient demonstrated the efficiency of the corrosion protection in sodium chloride media, including protection against pitting corrosion. © 2009 Elsevier Ltd. All rights reserved. Source

Meth S.,Bar - Ilan University | Meth S.,University of Southern California | Savchenko N.,Oil Refineries Ltd. | Viva F.A.,University of Southern California | And 3 more authors.
Journal of Applied Electrochemistry | Year: 2011

The corrosion protection of stainless steel (SS 316L) provided by layers of SiO2 and by siloxane-anchored self-assembled monolayer (SAMs) was assessed by cyclic voltammetry (CV) and by potentiostatic current transient in sodium chloride media. The SAMs were composed of octadecyltrimethoxysilane anchored onto a thin (1-2 nm) layer of SiO2. The initial SiO 2 layer was obtained by treatment with tetraethoxyorthosilicate. Successive layers were added by applying the alkylsiloxane and then oxidatively removed by treatment using a UV-ozone cleaner. Though SAMs have been used as corrosion barriers in other contexts, it is shown that successive cycles of SAM deposition and ablation provide an extended SiO2 thin-covering layer that protects stainless steel against pitting and general corrosion. © 2011 Springer Science+Business Media B.V. Source

Groysman A.,Oil Refineries Ltd. | Groysman A.,ORT Braude College | Siso R.,Oil Refineries Ltd. | Siso R.,ORT Braude College | Siso R.,S.B.A. Metal Works Ltd.
Materials Performance | Year: 2012

Aboveground gasoline, kerosene, diesel oil, and fuel oil tanks were inspected at an oil refinery to determine the rates of corrosion in the shells, floors, and floating and fixed roofs. Tank diameters varied from 23.7 to 36.6 m, and the height was 12.8 m. The shells of these tanks consisted of seven 1.8-rn high courses. The documentation of the ASTs did not indicate the type of CS. Traditional ultrasonic testing was used for measuring thickness of the metallic parts, floors, courses, roofs, and pontoons. The minimum acceptable thickness according to API 653 is 2.54 mm for floors and 2.6 mm for roofs. Corrosion rates were calculated based on the measurements of the seven courses of the shell of a typical gasoline AST. The floors in kerosene tanks were in good condition. Corrosion rates ranged from 0.04 to 0.1 mm/y. Similar to kerosene tanks, the shells usually exhibit no corrosion. Antistatic coatings of interior surfaces of shells in gasoline tanks was recommended. Source

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