Diaz-Guillen J.C.,CIMAV |
Diaz-Guillen J.C.,Corporacion Mexicana de Investigacion en Materiales S.A |
Vargas-Gutierrez G.,CINVESTAV |
Granda-Gutierrez E.E.,Corporacion Mexicana de Investigacion en Materiales S.A |
And 4 more authors.
International Journal of Electrochemical Science | Year: 2012
Plasma assisted duplex processes, such as nitriding post-oxidation, has been the focus of recent research publications looking to optimize wear and corrosion performance of several industrial components. High efficiency, process control as well as low energy consumption and clean technologies suggest that these processes are good alternatives for replacing the environmental harmful electrochemical techniques. An important challenge during post oxidation step is to avoid, as much as possible, the formation of hematite (Fe2O3) and to produce layers with a high content of high corrosion resistance magnetite (Fe3O4). In the present work, pulsed DC plasma post oxidation was used in order to obtain hematite-free magnetite layers on plasma nitrided AISI 4340 steel in order to improve its corrosion resistance. The effect of oxidation time (15, 30 and 45 minutes) on crystalline phases content and electrochemical corrosion performance was evaluated. Rietveld analysis of X ray diffraction data shows an increase in magnetite content and a decrease in Fe3N content after the post-oxidation period. Corrosion performance of nitrided AISI 4340 steel was significantly enhanced by the smoothest surface and the hematite-free magnetite layer obtained after pulsed post-oxidation process.
Mendez G.M.,Corporacion Mexicana de Investigacion en Materiales SA |
De Los Angeles Hernandez M.,Technological Institute of Nuevo Leon |
Gonzalez D.S.,Corporacion Mexicana de Investigacion en Materiales SA |
Proceedings of the 2011 11th International Conference on Hybrid Intelligent Systems, HIS 2011 | Year: 2011
A novel learning methodology based on a hybrid mechanism for training interval singleton type-2 Takagi-Sugeno-Kang fuzzy logic systems uses recursive orthogonal least-squares to tune the type-1 consequent parameters and the steepest descent method to tune the interval type-2 antecedent parameters. The proposed hybrid-learning algorithm changes the interval type-2 model parameters adaptively to minimize some criterion function as new information becomes available and to match desired input-output data pairs. Its antecedent sets are type-2 fuzzy sets, its consequent sets are type-1 fuzzy sets, and its inputs are singleton fuzzy numbers without uncertain standard deviations. As reported in the literature, the performance indices of hybrid models have proved to be better than those of the individual training mechanisms used alone. Experiments were carried out involving the application of the hybrid interval type-2 Takagi-Sugeno-Kang fuzzy logic systems for modeling and prediction of the scale-breaker entry temperature in a hot strip mill for three different types of coils. The results demonstrate how the interval type-2 fuzzy system learns from selected input-output data pairs and improves its performance as hybrid training progresses. © 2011 IEEE.
Corrosion behavior of API X70 steel welded for process double submerged arc immersed in different corrosives environments [Comportamiento a la corrosión del acero API X70 soldado por el proceso de doble arco sumergido inmerso en diferentes medios corrosivos]
Montes O.F.,S.A. de C.V. COMIMSA |
Garces R.S.,Corporacion Mexicana de Investigacion en Materiales S.A. |
Reyes Reyes F.A.,S.A. de C.V. COMIMSA |
Robledo P.C.Z.,Autonomous University of Nuevo León |
And 2 more authors.
Soldagem e Inspecao | Year: 2016
The steels API X70 are applied in construction and fabrication of pipeline for transport of hydrocarbons, however, to lapse time are degrade due to environment to which are exposed, influencing on mode and corrosion rate on surface base metal (BM), heat zone affected (HAZ) and fusion zone (FZ). In order to know and evaluate the corrosion susceptibility in joints of API X70 steel submitted to different corrosives environment, several tests were carried out by process of double submerged arc welding (DSAW), which were immersed in different electrolytes: Sodium Chloride (3.5% NaCl) and Water (H2O) at room temperature for know its behavior. Electrochemical techniques were used of electrochemical noise (EN) and cyclic polarization curves (CPC) to obtain mode and corrosion rate produced for each of the samples analyzed, included the three zones: BM, HAZ and FZ. Further, characterization techniques were used such as optical microscopy (OM) and scanning electron microscopy (SEM) for superficial analysis. The welds’ majoirity have a mixed corrosion, with higher corrosion rate in 3.5% NaCl. © 2016, Universidade Federal de Uberlandia. All Rights Reserved.
Aguilar-Otero J.R.,Corporacion Mexicana de Investigacion en Materiales SA |
Lopez-Ojeda L.,SA de CV
Global Congress on Process Safety 2012 - Topical Conference at the 2012 AIChE Spring Meeting and 8th Global Congress on Process Safety | Year: 2012
Risk based inspection (RBI) is defined as a risk based analysis for assessment loss of containment scenarios, assuming that risk is managed thru inspection activities or inspection plans. Besides the main goal of an RBI study which is identify high risk equipment and piping, to focus inspection resources, it can be used as a risk management tool, because of its consistency and straightforward methodology for risk calculation. Risk, for Risk-based inspection, can be expressed in many indicators, either qualitative or quantitative. On the quantitative side, financial risk (dollars/yr) and/or area risk (m2/yr) can be used, but also individual and societal risk could be used, just to say some; this risk indicators will help to prove the benefits of the actions taken to manage risk inside a process plant, refinery or petrochemical facility; also will help owners and stakeholders to demonstrate, that they are making enough efforts to keep their facilities safe for workers and for the people who live surrounding the plant and the rest of the community. The intention of this paper is to show a full risk management application for the RBI methodology beyond the inspection plans as well as to propose a methodology for risk index calculation, taking advantage of the large amount of information generated by the risk analysis developed in inspection planning. This paper will show the risk reduction in terms of risk to the population and people inside a process plant (workers), represented by the risk contours and F-N curves. The study was developed for several chemical process plants inside a 190 MBPd crude oil refinery, surrounded by an urban area with high population density and a shoreline. Once we have identified the high risk components (pressure vessels and piping) as a result from the RBI study, we evaluated them to assess the inspection plans impact and benefits for managing (reduce) the risk, specifically individual risk and societal risk. This methodology consists in both, a consequence analysis and a frequency of failure analysis. The consequence assessment for the high risk components, require a definition for the conditions that will be used on the scenario modeling, just to keep consistency on the expected results. The scenario was defined as a rupture scenario, represented by a catastrophic rupture; this scenario was modeled to get as an outcome the affected area. The frequency analysis requires the failure rates results from the RBI study, evaluating the frequency of failure without the inspection plan and after that, the frequency of failure with the inspection plan. The inspection plan is the risk mitigation action. So, we calculate two risk values, one for the "without plan" option and other for the "with plan" option. Then we compare both risk values to evaluate the benefits. Results are showed graphically using risk contours for individual risk, F-N curves for societal risk, and mathematically in m2/yr. Individual risk are used to identify places of particular vulnerability around the facility, like hospitals, neighborhoods or commercial areas. Societal risk was evaluated to assess how many people may be affected by the release of hazardous materials, meanwhile, financial risk was used to rank high risk components and focus management efforts on them.
Aguilar-Otero J.R.,Corporacion Mexicana de Investigacion en Materiales SA |
Lopez-Ojeda L.,Corporacion Mexicana de Investigacion en Materiales SA
12AIChE - 2012 AIChE Spring Meeting and 8th Global Congress on Process Safety, Conference Proceedings | Year: 2012
A full risk management application for the risk based inspection (RBI) methodology beyond the inspection plans is presented. A methodology for risk index calculation is proposed, taking advantage of the large amount of information generated by the risk analysis developed in inspection planning. The risk reduction in terms of risk to the population and people inside a process plant (workers), represented by the risk contours and F-N curves, is presented. The study was developed for several chemical process plants inside a 190,000 bpd crude oil refinery, surrounded by an urban area with high population density and a shoreline. The scenario was defined as a rupture scenario, represented by a catastrophic rupture. This scenario was modeled to get an outcome of the affected area. The frequency analysis requires the failure rates results from the RBI study, evaluating the frequency of failure without the inspection plan and after that, the frequency of failure with the inspection plan. The inspection plan is the risk mitigation action. Two risk values, one for the "without plan" option and other for the "with plan" option, are calculated. Both risk values are compared to evaluate the benefits. This is an abstract of a paper presented at the 2012 AIChE Spring Meeting and 8th Global Congress on Process Safety (Houston, TX 4/1-5/2012).