Herbert Leopold GABRYŚ
Power industry in Poland before the end of 2016
References are made to the situation of the Polish power industry at the backround of the Global Climate Agreement requirements. Presented are results achieved by power companies divided into separate groups of power generation and distribution. A comparison is then made between results achieved by these companies in the first half of 2016 with the ones from 2015 respectively. Compared is also the structure of electric energy production in the OECD countries and in Poland during the same period. Attention is turned to the production downward trends. And instead of the summary, a few questions are asked concerning key challenges that will be faced by the currently being prepared strategy of further development of the Polish power industry.
Keywords: Global Climate Agreement, Polish power industry condition, conditionings of the future strategy and power policy analysis
Grzegorz WERNER, Patrycja ŻUPA-MARCZUK, Marek KOŁODZIEJ, Wojciech GŁOWACKI
Experience from inspection and diagnostics of catalytic flue gas denitrification installation
Execution of several dozens of guarantee and optimization tests of catalytic flue gas denitrification installations, expert knowledge and a many years’ experience in emission measurements and technical consulting allowed „ENERGOPOMIAR” Sp. z o.o. to develop a new service in the Polish market encompassing inspection and diagnostics of SCR (Selective Catalytic Reduction) installations. It is the key service activity to keep operational factors on the proper level during longer periods and a very important one for the optimum equipment maintenance management. The service consists in a detailed audit of SCR installations, involving the assessment and diagnostics of the installations during their operation, as well as in inspections carried out during standstills and including thorough testing of catalyst inserts performed by an independent expert teams.
Keywords: „ENERGOPOMIAR” Sp. z o.o., SCR–Selective Catalytic Reduction, catalytic flue gas denitrification installations, diagnostics
Janusz BADUR, Daniel SŁAWIŃSKI, Sebastian KORNET, Tomasz KOWALCZYK, Mateusz BRYK,
Piotr J. ZIÓŁKOWSKI, Michał STAJNKE, Paweł ZIÓŁKOWSKI
Overdesign limitations from the maintaining availability of large steam turbine
In this paper risks of cogeneration work steam turbine with Revenable Source have been showed. The greatest probability of damage in steam turbine have been defined. Elasto-plastic adaptation in material for shorted time of start up and shotdown steam bloks have been proposed. The numerical simulation have been performed via thermal-FSI procedure.
Keywords: steam turbine, performance, damage
Andrzej BŁASZCZYK, Adam PAPIERSKI, Mariusz SUSIK
The role of numerical flow calculation in pumps modernizations
The article discusses the role of numerical modeling of three-dimensional flows in the processes of design and optimization of hydraulic elements of the pumps in terms of realization of the maximum possible efficiency, and identify the causes of their poor work in the existing pump systems. Shows the location of numerical methods in the design procedure of pumps.
Keywords: modernization of pumps, numerical modeling of flows
Piotr FURMAŃCZYK, Mirosław GAJEWSKI, Justyna KASIŃSKA, Tadeusz ORZECHOWSKI
Modification of mischmetal an effective way to increase the properties of steel for power engineering
The paper presents the results of the modification influence of mischmetal on GP240GH non alloyed cast steel, G17CrMo5–5 martensitic cast steel and Cr – Ni austenitic cast steel stabilized with titanium. Experiments were carried out on industrial melts, which were prepared in an electric induction furnace with a capacity of 3000 kg and an alkaline liner of the crucible Mischmetal was introduced in portions into the ladle during tapping the steel from the furnace. It showed a highly advantages and comprehensive influence of rare earth metals on the structure and properties of cast steel.
Keywords: mischmetal, modification of cast steels
Grzegorz GOLAŃSKI, Jerzy KUPCZYK, Janusz DOBRZAŃSKI, Adam ZIELIŃSKI, Stanisław MROZIŃSKI
Influence of cooling rate after underannealing on microstructure and mechanical properties of L20HM cast steel
The paper presents the results of research on the microstructure and mechanical properties of L20HM cast steel after around 186 000 hours of service at the temperature of 535°C and after the regenerative heat treatment. The heat treatment of the examined cast steel consisted in full annealing and the subsequent underannealing with cooling at three different rates. Depending on the cooling rate applied, different microstructure and mechanical properties were obtained in the examined cast steel. Performed tests have shown that, as a result of accelerated cooling from the two-phase range, there is a possibility of raising the strength properties at the same time maintaining the required impact energy.
Keywords: cast steel L20HM, investigation of microstructure, investigation of mechanical properties
Adam HERNAS, Iwona BEDNARCZYK, Adrian MOŚCICKI, Stanisław FUDALI, Jerzy HAJDA
Microstructure and toughness of HR3C steel after ageing at 650°C
The HR3C steel is recommended for long-term service under creep conditions at up to 650-660°C. The paper presents some results of microstructure analysis and fracture morphology and toughness of welded joints made of HR3C steel after cyclic heat treatment at 650°C. Results confirmed the unsatisfactory ductile properties below KV<40 J with brittle nature of cracking as a result of mainly a tendency towards the formation of unfavorable morphology of M23C6 carbides at the coarse-grain and twin boundaries of austenite.
Keywords: steel HR3C, investigation of microstructure, investigation of ductilit
Sebastian KORNET, Paweł ZIÓŁKOWSKI, Janusz BADUR
Destructive tests of butt weld-joints made on high-strength steels S420 G2+M underwater at the level of 30 meters depth
This paper presents the results of destructive tests on butt joints created in aqueous environment at 30 meters depth. High strength S420 G2+M constructional (ferrite-pearlite structure) steel, bolstered by means of controlled rolling, was used as welded material. The joint was made in a simulator for welding and cutting at great depths. Method of local dry-chamber welding was applied. Pure argon was used as the shielding gas. In accordance with European standards (PL-EN), a destructive test specimen were made from joints. Destructive testing was carried out as follows: micro- and macro-metallographic test, static tensile test and the test of bending.
Keywords: butt joint, metallographic investigations
Barbara KOŚCIELNIAK, Adam HERNAS, Sławomir KĄC
High temperature corrosion of dissimilar welded joints of martensitic and austenitic steels
The paper presents the results of corrosion and structural researches of dissimilar welded joints of heat resistant ferritic steels (T91, VM12, 13CrMo4-5), austenitic steels (Super 304 H, T347) and nickel superalloy IN 617, after undergoing the process of corrosion in an environment containing sulphur and chlorine at temperature of 650°C. Welds were made with the use of laser and TIG methods. The aim of the study was to asses of high-temperature corrosion resistance of dissimilar joints, which were made of the recommended materials for the steam superheater in supercritical and biomass boilers at a temperature of 650°C. Research has shown a very good corrosion resistance of austenitic in aggressive medium. In addition, laser-welded joints are characterized by relatively more favorable corrosion properties than joints welded by TIG method.
Keywords: welded joint, corrosion investigation and metallography
Andrzej KUREK, Justyna KOZIARSKA, Tadeusz ŁAGODA
Application of the theory of large deformation in uniaxial tension compression of selected metals
The paper presents the differences in the fatigue curves resulting from the inclusion in the calculation of the assumptions of the theory of large deformations. This is a problem particularly important in the case of high-strength, elastic-plastic materials operating under low-cycle fatigue.
Keywords: large displacement theory, stretching and compression of metals
Andrzej KUREK, Paweł KUREK, Mariusz ŁAPKA
Effect of heat treatment on the fatigue life of the steel-titanium bimetal
The paper presents fatigue tests results of bimetal steel-clad titanium explosively welded. The study involved specimens made of bimetal which is a combination of steel S355J2 with titanium SB 265 G1, which was imposed in the process of material cladding and both basic materials. Both heat treated and not specimens where tested.
Keywords: bimetal steel-titanium, fatigue life, heat treatment
Marta KUREK, Mirosław W. MRZYGŁÓD, Tadeusz ŁAGODA
Application of a new model for estimating the fatigue life of the design of structures operating at elevated temperatures
The paper concerns the estimation of fatigue life of cylindrical specimens made of steel SUS304 under cyclic proportional tension-compression and torsion. Fatigue tests were performed at elevated temperature (923 K). The paper presents a comparison of the fatigue life calculated by own model and model of Carpinteri. Both models are based on the concept of the critical plane. In the example of the fatigue design, the impact of examined criteria on the structure shaping is shown.
Keywords: fatigue life assessment, structure shaping
Katarzyna MAKOWSKA, Zbigniew L. KOWALEWSKI
Evaluation of degradation level in ferromagnetic materials by means of magnetic techniques
The paper describes and compares the results of two research methods based on the phenomena of Barkhausen effect and magnetoacoustic emission. An influence of the magnetizing current frequency on the values of measurements captured is studied. The attention was also drawn into changes of magnetic parameters as a function of prior deformation level of material, thus reflecting variations of its mechanical properties.
Keywords: ferromagnetic materials, magnetic techniques, the phenomena of Barkhausen effect, magnetoacoustic emission
Kazimierz MUTWIL, Marek CIEŚLA, Grzegorz JUNAK, Tomasz KAWAŁA
Effect of plastic working on mechanical characteristics of tube bends made of the 14MoV6-3 steel
Procedures used to design electric power systems are based on an assumption that mechanical properties of all elements the given system is made of correspond to the mechanical properties of the relevant material in the as-delivered condition. Typical pipeline elements which require hot plastic working are tube bends manufactured by application of diverse methods. At present, large diameter tubes are increasingly often bent to relatively small radii by means of a bending machine and using zonal induction heating. The tube bending process involves considerable non-uniformity of stress and strain distribution in the bend forming area, which may exert significant impact on its mechanical properties. What is required of tube bends is that their strength parameters are sufficiently high, similar to those of non-deformed tube sections. This article provides results of studies of basic mechanical properties of the tube material as well as a tube bend made of the 14MoV6-3 steel. For testing purposes, the material was sampled from an as-delivered tube and from selected tube bend zones characterised by diversified degree of deformation.
Keywords: tube bending, mechanical properties, creep, low cycle fatigue, durability
Jerzy OKRAJNI, Mariusz TWARDAWA
The influence of different kinds of loading of the power plant components on the creep behaviour and fatigue processes
Basic loads in power plants components have been presented in the paper. The creep, the stress relaxation and fatigue processes have been discussed. Methods of the computer modelling have been used to describe the characteristics of these processes. The method of the evaluation of the stress-strain characteristics has been presented. It has been justified that each of considered loads leads to the different behaviour of the components and different characteristics should be applied to the description of phenomena of the formation of damage in components under consideration. The crucial role of the thermo-mechanical fatigue of thick-walled components of boilers which operate under increased temperature and pressure has been underlined.
Keywords: power plant components, creep processes, stress relaxation, fatigue
Tadeusz PAŁA, Ihor DZIOBA, Robert PAŁA
The microstructure and mechanical properties of the butt tubes laser welded joints of a ferritic steels
In the paper are presented results of testing performed on but tubes welded joints, which were made of two steel grades: 16Mo3 and P235GH. The microstructural tests were made, hardness distributions were established and also strength properties and fracture toughness for weld zones of welded joints were stated. The obtained results showed that laser welding technology allows to obtaining the joints of high quality and strength on the level eliminat-ing brittle fracture occurrence.
Keywords: butt tubes joints, laser welding, microstructure, mechanical properties
Tadeusz PAŁA, Ihor DZIOBA
Experimental-numerical analysis of strength of laser welded joints of S960QC steel
In the article presented results of experimental tests of laser welded joints that were used to created a numerical FEM model. The experimental tests included determination of hardness distribution and mechanical properties in particular sections of the welded joint. Uniaxial tension tests of the welded joint were carried out by means of Aramis videoextensometer, which enabled registration of displacements on the specimen surface and established of the maps of strain fields on the surface of the welded joint. Numerical simulation of the welded joint loaded were carried out on the basis of determined strength characteristics and FEM model.
Keywords: laser welded joints, strength analysis, numerical model
Janusz POSPOLITA, Wojciech POSPOLITA, Roman STACHOWICZ
The indicators of installation wear in coal pulverizers
The current monitoring of coal pulverizers allows to maintain the desired quality of coal dust as well as reduction of energy consumption for own needs. The paper presents three indicators that can be used to assess the degree of installation wear of grinding elements. These indicators are: dust quality, the specific energy consumption for the preparation of coal dust and the height of material layer under grinding rolls. The study analyzed results of mills type RP performed at intervals of several years in the Opole Power Plant. The article presents how these indicators are associated with the working time of grinding components. It presents also some conclusions about the possibility of assessing technical condition of pulverizers based on the monitoring of the indicators.
Keywords: coal mill, operation parameters, technical state assessment
Tomasz STECHNIJ, Stanisław ZABORSKI, Dariusz POROŚ
The correlation of contact surface roughness of selected materials from the contact resistance
The article is a brief studies issues contact resistance conductors as a function of the parameters of surface roughness. Completed dozens of attempts on his own bench, used materials of various structures of geometric surfaces, prepared for the purpose of the experiment. The principal goal of the authors of the test cycle is an empirical assessment of changes in contact resistance in the context of the techniques of surface treatment of contacts.
Keywords: resistance of contact system of conductors, geometric structure
Dimensions-deformation nonuniqueness resulting from the EU directive concerning pipes bending for large and small deformations
In paper the relations to calculate the maximum value of relative strains valid for the case of large and small deformations, which occur in a process of bending of tubes on benders, in stretched layers of tubes, are presented in this work on the basis of EU-Directive concerning production of pressure equipment. It has been shown that for large deformations that occur during bending of the pipes on knees, logarithmic strain measures (real) and relative strain measures give different values of strain but equal wall thicknesses in the bending zone. For the case of relative measures of deformations valid for small deformations different are both values of components and intensities of the deformation and thicknesses of the partition wall. Logarithmic measures are frequently used in engineering practice and are valid for large and small deformations. Reverse expressions were also derived to calculate the required initial wall thickness of the tube to be bent, in order to obtain the desired wall thickness of knee after bending. Computational results were presented in the form of graphs.
Keywords: pipes bending, strains, ambiguity of deformation and dimensions
Paweł ZIÓŁKOWSKI, Janusz BADUR, Grzegorz BZYMEK
Modelling of the steam turbine control stage of turbine type 360 MW
This paper concerns the issues of modeling the work steam turbine control stage in order to increase the safety of regulation of the turbine type 360 MWe. At the current load of steam turbine, more detailed computational tools like FSI (Fluid Solid Interaction) are required, which allow determining the liquid - solid interaction. This article describes the results of FSI analysis in two aspects: at first shows typical flow aspects solved by methods of CFD (Computational Fluid Dynamic) and secondly strength issues using CSD (Computational Solid Dynamic) that describes the efforts of the selected components of the turbine. As well management of lifetime was briefly discussed. Presented analysis should be considered as satisfied in the process of increase availability of steam turbine control stage as well the enhancement of safety of operation of steam turbine.
Keywords: steam turbine control stage, modeling, turbine control