Повышение качества регулирования натяжения полосы агрегата непрерывного горячего цинкования

The paper studies a system of interconnected electric drives in the operational area of the continuous hot dip galvanizing unit located in the coating shop at PJSC Magnitogorsk Iron and Steel Works (PJSC MMK). It particularly focuses on the mechanical part with elastic elements and electric drive control systems. The paper aims at studying the existing operating modes of electric drives of the main mechanisms in the operational and output areas of the galvanizing unit; identifying ways to improve the static and dynamic performance of the interconnected electric drives system; developing an improved control system that provides for the better dynamic performance with indirect strip tension control. The authors propose a new control system for the operational area electric drives with corrective speed feedback. The dynamic characteristics of the traditional and the proposed systems were studied using a mathematical model of electric drives of the analyzed section with account to their interconnection via an elastic strip. The model accounts for eight electric drives, i.e., a hot tension station, tension stations no. 3, 4, 5, 6 and a training stand. Each electric drive is modeled with account for mecha­nical inertia and a (speed or torque) control system. The comparative analysis of tension control quality indicators for these systems proved the advantages of the developed system. The research outcomes can be used for similar units of continuous strip processing, featuring the technological line sections with a significant length of the strip between the adjacent electric drives.Объектом исследования является система взаимосвязанных электроприводов технологической зоны агрегата непрерывного горячего цинкования цеха покрытий ПАО «Магнитогорский металлургический комбинат» (ПАО «ММК»), в частности механическая часть с упругими элементами и системы управления электроприводами. Целями работы являются: исследование существующих рабочих режимов электроприводов основных механизмов технологической и выходной зон агрегата цинкования, выявление способов улучшения работы системы взаимосвязанных электроприводов в статических и динамических режимах, разработка усовершенствованной системы управления, обеспечивающей улучшенные динамические показатели при косвенном регулировании натяжения полосы. Предлагается новая система управления электроприводами технологической зоны с корректирующей обратной связью по скорости. Динамические характеристики традиционной и новой систем исследовались на математической модели электроприводов исследуемого участка агрегата с учетом их взаимосвязи через упругую полосу. Модель учитывает электроприводы: горячая натяжная станция, натяжные станции № 3, 4, 5, 6 и дрессировочная клеть. Каждый электропривод моделируется с учетом механической инерции и системы управления скоростью или моментом. Сравнительный анализ показателей качества регулирования натяжения для указанных систем показал преимущества разработанной системы. Результаты работы могут быть использованы на аналогичных агрегатах непрерывной обработки полосы, в которых присутствуют участки технологической линии со значительной протяженностью полосы между соседними электроприводами

DEVELOPMENT AND MODELING OF MEMBRANE PROCESSES FOR THE REGENERATION OF ACID PICKLING SOLUTIONS

The doctoral thesis focuses on a novel integrated process for the recovery and valorisation of acid and metal salts present in the waste solutions of the pickling process. The proposed process is based on the integration of two innovative membrane technologies, the Diffusion Dialysis and the Membrane Distillation, coupled with a reactive precipitation section. This hybrid process allows the recovery and the enhancement of waste solutions, as well as optimal operating conditions for the continuous pickling process, thus improving its efficiency. Hydrochloric acid recovery was assessed through a detailed study on the Diffusion Dialysis process by implementing a wide experimental campaign using artificial solutions produced in laboratory, in order to understand and characterize the system. A mathematical model was developed with time and space distributed-parameters structure for the effective simulation of steady state and transient batch operations, thus providing an operative tool for the design and optimization of DD units. Selective separation of metal salts was reached by precipitating ferric hydroxide and maintaining ammonium and zinc chlorides in solution, which can be used as fluxing solution in the galvanizing process itself, thus implementing the typical Circular Economy concept. The feasibility of the proposed process is demonstrated through the use of a purposely developed process simulator able to predict steady state operation of the integrated process and to perform sensitivity analysis for the identification of the best operating conditions of the system. An experimental campaign was carried out with a demonstrator unit, jointly designed and constructed by Fraunhofer ISE (Freiburg, Germany), eventually installed in the real industrial environment of Tecnozinco s.r.l hot-dip galvanizing plant in Carini, Sicily. The campaign assessed the integration performance of the different units and the process reliability, resulting in a minimization of spent pickling solution disposal and in high quality recovered compounds. An engineering economic analysis was carried out in order to assess the economic feasibility of the proposed process. The economic model was implemented in the gPROMS simulation platform and was used to conduct an optimization analysis, defining the optimal operational and design conditions for which the process is more profitable and performing. The process simulator was also used to provide a scale-up of the demonstrator plant. The results have shown that the process has a good potential for industrial implementation, thanks to the economic and environmental benefits

Decision making for risk evaluation: integration of prospect theory with failure modes and effects analysis (FMEA)

The aim of the present study is to overcome some of the limitations of the FMEA method by presenting a theoretical base for considering risk evaluation into its assessment methodology and proposing an approach for its implementation. Fuzzy AHP is used to calculate the weights of the likelihood of occurrence (O), severity (S) and difficulty of detection (D). Additionally, the Prospect Theory-based TODIM method was integrated with fuzzy logic. Thus, fuzzy TODIM was employed to calculate the ranking of potential failure modes according to their RPNs. In order to verify the results of the study, in-depth interviews were conducted with the participation of industry experts. The results are very much in line with Prospect Theory. Therefore, practitioners may apply the proposed method to FMEA. The most crucial failure mode for a firm’s attention is furnace failure followed by generator failure, crane failure, tank failure, kettle failure, dryer failure, and operator failure, respectively. The originality of this paper consists in integrating Prospect Theory with the FMEA method in order to overcome the limitations naturally inherent in the calculation of the FMEA’s Risk Priority Numbers (RPNs).N/

Mining association rules for the quality improvement of the production process

Academics and practitioners have a common interest in the continuing development of methods and computer applications that support or perform knowledge-intensive engineering tasks. Operations management dysfunctions and lost production time are problems of enormous magnitude that impact the performance and quality of industrial systems as well as their cost of production. Association rule mining is a data mining technique used to find out useful and invaluable information from huge databases. This work develops a better conceptual base for improving the application of association rule mining methods to extract knowledge on operations and information management. The emphasis of the paper is on the improvement of the operations processes. The application example details an industrial experiment in which association rule mining is used to analyze the manufacturing process of a fully integrated provider of drilling products. The study reports some new interesting results with data mining and knowledge discovery techniques applied to a drill production process. Experiment’s results on real-life data sets show that the proposed approach is useful in finding effective knowledge associated to dysfunctions causes

Advanced Methods of Power Load Forecasting

This reprint introduces advanced prediction models focused on power load forecasting. Models based on artificial intelligence and more traditional approaches are shown, demonstrating the real possibilities of use to improve prediction in this field. Models of LSTM neural networks, LSTM networks with a SESDA architecture, in even LSTM-CNN are used. On the other hand, multiple seasonal Holt-Winters models with discrete seasonality and the application of the Prophet method to demand forecasting are presented. These models are applied in different circumstances and show highly positive results. This reprint is intended for both researchers related to energy management and those related to forecasting, especially power load

Environmental Sustainability of Current Waste Management Practices

Environmentally sustainable and economic waste management is of significant importance to various fields, including the healthcare, mining, industrial, metal-processing, municipal and commercial sectors. This book provides a global perspective and covers a wide range of state-of-the-art topics on waste management, recycling, material and energy recovery, industrial waste, etc. Information in the form of in-depth reviews and research articles will be a valuable resource for academics, professionals and regional as well as international organizations

Highway Bridge Redesign

The goal of this MQP was to analyze different possible replacement strategies for a specific highway bridge to design the most easily implementable and efficient replacement. Design of the bridge elements was completed in accordance with the AASHTO LRFD Bridge Specification and was aided by the use of software. The final presentation included a structural design of the selected superstructure and substructure with accompanying construction and traffic planning, as well as a cost estimate of direct and indirect costs

Multi-Material Metal Casting: Metallurgically Bonding Aluminum to Ferrous Inserts

Properties of cast aluminum components can be improved by strategically placing ferrous inserts to locally improve properties such as wear resistance and stiffness. A cost-effective production method is to cast-in the insert using the solidification of the molten aluminum as a joining method. Metallurgically bonding between the metals could potentially improve both load and heat transfer across the interface. The metallurgical bond between the steel and the aluminum has to be strong enough to withstand stresses related to solidification, residual stresses, thermal expansion stresses, and all other stresses coupled with the use of the component. Formation of a continuous defect free bond is inhibited by the wetting behavior of aluminum and is governed by a diffusion process which requires both energy and time. Due to the diffusional nature of the bond growth in combination with post manufacturing heat treatments defects such as Kirkendall voids can form. The effect of aluminum alloying elements during liquid-solid bond formation in regards to microstructural changes and growth kinetics has been described. A timeframe for defect formation during heat treatments as well as microstructural changes has been established. The effect of low melting point coatings (zinc and tin) on the nucleation of the metallurgical bond has been studied as well the use of a titanium coating for microstructural modification. A set of guidelines for successful metallurgical bonding during multi- material metal casting has also been constructed

A Process to Implement an Artificial Neural Network and Association Rules Techniques to Improve Asset Performance and Energy Efficiency

In this paper, we address the problem of asset performance monitoring, with the intention of both detecting any potential reliability problem and predicting any loss of energy consumption e ciency. This is an important concern for many industries and utilities with very intensive capitalization in very long-lasting assets. To overcome this problem, in this paper we propose an approach to combine an Artificial Neural Network (ANN) with Data Mining (DM) tools, specifically with Association Rule (AR) Mining. The combination of these two techniques can now be done using software which can handle large volumes of data (big data), but the process still needs to ensure that the required amount of data will be available during the assets’ life cycle and that its quality is acceptable. The combination of these two techniques in the proposed sequence di ers from previous works found in the literature, giving researchers new options to face the problem. Practical implementation of the proposed approach may lead to novel predictive maintenance models (emerging predictive analytics) that may detect with unprecedented precision any asset’s lack of performance and help manage assets’ O&M accordingly. The approach is illustrated using specific examples where asset performance monitoring is rather complex under normal operational conditions.Ministerio de Economía y Competitividad DPI2015-70842-

Modificação superficial de nanocontentores de inibidores de corrosão para melhoria da compatibilidade com revestimentos protetores

The application of organic coatings is one of the most widely used preventive measures to protect metal alloys against corrosion. Typically, anti-corrosion coatings combine passive and active protection, the former being based upon barrier effect of the matrix against ingress of active species and the later due to the presence of corrosion inhibitors directly dispersed in the coating matrix. Nevertheless, the direct addition of corrosion inhibitors to coating formulations often leads to detrimental effects, thus impairing the overall coating performance. To circumvent this limitation, micro and nanocontainers as hosting structures for storage and controlled release of corrosion inhibitors, have been proposed. If this release is triggered by adverse conditions that result in corrosion initiation self-healing takes place, which can bring great benefit to high-performance applications. The work presented in this thesis aims at modifying the nanocontainers surface in order to enhance the role of inhibition and barrier properties of the coatings as well as improving their dispersibility and compatibility within the coating. This latter part of the study had not been in general addressed in the scientific literature and requires interaction with the coating producer in order to match the desired properties for a commercial formulation. Two nanocontainers to store the corrosion inhibitors were selected: layered double hydroxides (LDH) and silica nanocapsules (Si_NC). The surface modification of LDH loaded with 2-mercaptobenzothiazole (2-MBT) with poly(styrene sulfonate)/poly(allylamine hydrochloride) by the layer-by-layer self-assembly technique allowed the incorporation of a second corrosion inhibitor, cerium nitrate, but at the same time improve the coating barrier properties of the hybrid sol-gel coatings. Moreover, the release profile of 2-MBT was also changed with this surface modification. This lab-scale work was extended to an industrial collaboration with a steel producer. In this case, the modification of gluconate loaded LDH with alginate lead to improvement in coating barrier properties of a polyamide-based coating. In the case of Si_NC several functional groups were grafted onto these silica-based nanomaterials, allowing a thorough analysis of the effect the surface chemistry on the dispersibility and compatibility with coatings. Tests were carried out in systems with increasing complexity from solvents, to hybrid sol-gel formulations and water- and solvent-based coating formulations industrially available. The coating barrier properties were mainly assessed by electrochemical impedance spectroscopy, often complemented with other electrochemical methods. Spectroscopic and surface-characterization techniques, and in some cases standard tests carried out under an industrial environment were also used. The results prove the importance that the surface modification has on the nanocontainer dispersibility and in the nanocontainer/coating compatibility. These results obtained show that surface modification of these nanocontainers can tune the interaction with coating matrix, opening prospects for the industrialization of these controlled-release technologies in the area of protective coatings.A aplicação de revestimentos orgânicos é uma das medidas preventivas mais utilizadas na proteção contra corrosão em ligas metálicas. Tipicamente, revestimentos anti-corrosão combinam proteção passiva e ativa, sendo a primeira baseada no efeito barreira do revestimento contra o ingresso de espécies ativas e a segunda devido à presença de inibidores de corrosão dispersos diretamente na matriz do revestimento. Não obstante, a adição direta de inibidores de corrosão a formulações de revestimentos leva normalmente a ocorrência de efeitos negativos, assim prejudicando a desempenho global do revestimento. De forma a contornar esta limitação, micro e nanocontentores, estruturas hospedeiras para o armazenamento e libertação controlada de inibidores de corrosão, têm sido propostos. Se esta libertação for desencadeada por condições adversas que resultam na iniciação de corrosão o efeito de autorreparação tem lugar, o que pode trazer grandes benefícios em aplicações de elevada desempenho. O trabalho apresentado nesta tese tem como objetivo a modificação superficial de nanocontentores a fim de melhorar o papel da inibição e das propriedades barreira de revestimentos, assim como a melhoria da dispersibilidade e compatibilidade dentro do revestimento. Este último é geralmente um tópico que não é abordado na literatura científica e que ao mesmo tempo necessita de um certo nível de interação dos produtores de formulações para revestimentos de forma a corresponder às propriedades desejadas numa formulação comercial. Dois nanocontentores, com comprovada atividade como reservatórios de inibidores de corrosão, foram selecionados: hidróxidos duplos lamelares e nanocápsulas de sílica. A modificação superficial de hidróxidos duplos lamelares intercalados com 2-mercaptobenzotiazol com poliestireno sulfonato/hidrocloreto de polialilamina pela técnica de automontagem camada-a-camada permitiu a incorporação de um segundo inibidor de corrosão, nitrato de cério, ao mesmo tempo melhorando as propriedades barreira do revestimento de sol-gel hibrido. Além de que, o perfil de libertação do 2-mercaptobenzotiazol também foi alterado com a modificação da superfície. Este trabalho à escala laboratorial foi estendido para uma colaboração industrial com um produtor de aço. Neste caso, a modificação de hidróxidos duplos lamelares intercalados com gluconato com alginato levou a melhorias nas propriedades barreira de um revestimento de base poliamida. No caso de nanocápsulas de sílica diversos grupos funcionais foram ligados a estes nano-materiais a base de sílica, permitindo uma análise detalhada do efeito que a química de superfície tem na dispersibilidade e compatibilidade com revestimentos. Testes foram realizados em sistemas com uma complexidade crescente, desde solventes, ate formulações de sol-gel hibrido e revestimentos comerciais de base aquosa e solvente. As propriedades barreira dos revestimentos foram, na sua maioria, avaliadas por espetroscopia de impedância eletroquímica, frequentemente complementada com diferentes técnicas eletroquímicas, espectroscópicas e de caracterização de superfície, e em alguns casos com testes padrão realizados em ambiente industrial. Os resultados provaram a importância que a modificação da superfície tem na dispersão dos nano-contentores e na compatibilidade entre nano-contentores e revestimentos. Os resultados obtidos demostram que a modificação da superfície destes nanocontentores pode permitir ajustar a sua interação com a matriz do revestimento, abrindo perspetivas para a industrialização destas tecnologias de libertação controlada na área dos revestimentos de proteção.Programa Doutoral em Ciência e Engenharia de Materiai