Marek SZROT, Janusz PŁOWUCHA, Paweł MOLENDA
Oxidation stability of regenerated mineral electro-insulating oils
Presented are here tests having in aim checking the oxidation resistance (ageing) of regenerated mineral electro-insulating oils. For transformers where the condition of liquid insulation requires some intervention, widely considered is the more and more now popular oil reconditioning service and also – as its alternative – replacement of oil with the new one. During tests the regenerated oils were compared with the most frequently chosen basic non-inhibited mineral oils.
Keywords: mineral electro-insulating oils, oxidation resistance of regenerated oils
Ryszard BARTNIK, Zbigniew BURYN, Anna HNYDIUK-STEFAN, Adam JUSZCZAK
Methodology and a continuous time mathematical model for selecting the optimum capacity of a heat accumulator integrated with a CHP plant
The production of additional amounts of electricity in a CHP plant throughout the peak load hours corresponding to the maximum level of electricity demand, as specified by the power system, and decrease of its output to meet the base load demand resulting from heat accumulation can provide a manner in which the economic efficiency of a CHP plant can be increased. The decision regarding the construction of a heat accumulation tank should be taken on the basis of an analysis of the economic efficiency of its exploitation. We can emphasize, however, that economic efficiency is only possible after a prior analysis of the technical aspects. The results of the latter form inputs for the subsequent economic analyses. This paper contains the results of a study in which a novel approach using continuous time notation was applied in the search for the optimum capacity of a heat accumulation tank to an existing CHP plant.
Keywords: a heat accumulator integrated with a CHP plant, selecting the optimum capacity of a heat accumulator, methodology and a continuous time mathematical model
Janusz BURACZEWSKI, Janusz BADUR, Paweł ZIÓŁKOWSKI, Tomasz KOWALCZYK, Mateusz BRYK
Twenty years of the first combined cycle gas turbine in Poland and what’s next?
The authors presented both operational data and literature studies related to the first combined cycle gas turbine, which was built in Poland twenty years ago. Due to it specificity of work, namely two types of fuels and different work regimes first as a combined heat and power block, and now as a condensation block – it undergone significant retrofitting and renovations, which provided a rich base of experience. However, despite the long working hours of the gas turbine and heat recovery steam generator, it can still be a significant source of power in the Polish Energy System, responding quickly to the needs of the Power Market.
Keywords: combined cycle gas turbine, operational data, specificity of work
Janusz DOBRZAŃSKI, Hanna PURZYŃSKA
Method to assess the material of steam power units pipelines after a long operation in creep conditions beyond design working time
Presented is the procedure of condition assessment and determination of further operation of steam pipelines material working in creep conditions far beyond the design working time. A brief review is made of proceeding steps that were taken in frames of the elaborated algorithm. The selected characteristic steps of the adopted procedure are discussed on the example of the material of a 200 MW power unit live steam pipeline elements made of the 14MoV6-3 steel.
Keywords: steam pipelines of power units, long operating time, creep conditions, assessment of a pipeline material
Janusz DOBRZAŃSKI, Hanna PURZYŃSKA
Method to assess the condition of a boiler drum material after a long operation beyond design working time
In the form of algorithm there is presented a method of proceeding to assess and then determine the time and conditions of further operation of boiler drums. Briefly discussed are individual steps of the proceeding. The selected characterisitic steps are discussed on the example of boiler drums made of fine-grained low-alloy steels 18CuMNT and 15NCuMNb.
Keywords: boiler drums, long time operation, assessment of a material condition
Zbigniew JAGUSZEWSKI, Piotr KUŚMIERSKI, Emil SZOPA
Use of the technology of ultrasound tests with Phased Array method for repair of coat of low pressure feedwater heater
The article below presents the method of repairing the coat of low pressure feedwater heater and presents technique of ultrasonic testing Phased Array (PA). The methodology of research based on previous conventional point thickness measurements was compared, and the ultrasound system enabling automatic and continuous registration of measurement results creating precise color images of the internal surface area, so-called corrosion maps including coordinates of measuring points.
Keywords: coat of low pressure feedwater heater, repairing with Phased Array method
Klaudia KLIMASZEWSKA, Paweł URBAŃCZYK, Grzegorz GOLAŃSKI
The effect of aging on the microstructure and properties of HR3C steels
The physical metallurgical tests were performed on HR3C steel in the as-received state and after the process of ageing at the temperature of 600oC and 700oC, at times up to 10 000 hours. The range of the conducted tests included: structural tests using the scanning electron microscopy and mechanical tests: measurement of hardness and impact strength tests. The HR3C steel in the as-received condition was delivered after supersaturation and was characterised by the austenitic microstructure with annealing twins and numerous primary precipitates. Such a structure ensured obtaining high ductility (notch toughness at the level of 212 J) and relatively low hardness of 176 HV30. The microscopic observations of the HR3C steel after the ageing process revealed significant changes in the microstructure consisting mostly in the tendency to form unfavourable morphology of the secondary phases precipitates on the boundaries of grains, inside the grains, as well as on single twin boundaries. These processes contributed to a decrease in ductility of the examined steel, at the concurrent growth of hardness. The more advanced precipitation processes were observed in the steel aged at the temperature of 700oC.
Keywords: the HR3C steel, steel microstructure, process of ageing, ductility
Tomasz KOWALCZYK, Paweł ZIÓŁKOWSKI, Janusz BADUR
A novel methane production in steam turbine power plants with carbon dioxide sequestration system
The paper presents a system of methane production from hydrogen from the electrolysis of water and carbon dioxide from coal combustion. An advantage of the proposed method is the simple construction and operation of the system as well as the possibility of increasing the flexibility of electricity production in the power plant, in particular the reduction of the tech-nological minimal electricity production during the power system load valleys. Modernization of the power unit into a polygeneration block gives the possibility of diversifying recipients of the produced energy. Moreover, the presented system enables the production of both methane and pure hydrogen, which is an additional advantage in the era of the developing hydrogen economy.
Keywords: steam turbine power plants, a novel methane production, carbon dioxide sequestration system
Katarzyna MAKOWSKA, Zbigniew L. KOWALEWSKI, Waldemar DUDDA, Paweł ZIÓŁKOWSKI, Janusz BADUR
Microstructural and Barhausen noise analysis of the exploited turbine blades
In the work a level of degradation of the exploited turbine blades using Barkhausen noise method and microscopic technique was examined. The hardness tests were performed. The influence of exploitation time on Barkhausen noise level with consideration and without consideration of the oxygen layer was determined.
Keywords: turbine blades, testing the level of degradation, Barkhausen noise method
Agata MERDA, Adam ZIELIŃSKI, Grzegorz GOLAŃSKI
Analysis of phase transformation in nickel-base alloy HR6W after ageing
The nickel-based HR6W alloy was subject to metallographic tests in the as-received state and after the ageing process at the temperature of 700oC and times up to 10 000 hours. The scope of the performed tests included the structural tests using optical microscopy and scanning electron microscopy, the identification of precipitates using electron diffraction TEM and the measurement of hardness. The tests showed that in the as-received state in the analysed alloy, only the MX type of precipitates occurred, and that the long-term ageing contributed to the precipitation of numerous particles of secondary phases: M23C6 carbides, Laves phase, and compound complexes. The intense course of precipitation processes resulted in the growth of hardness of the examined alloy.
Keywords: the nickel-based HR6W alloy, ageing process
Stanisław MROZIŃSKI, Zbigniew LIS
Influence of test conditions on the fatigue characteristics of steel P91
Low-cycle fatigue tests of P91 steel made in two temperatures, T = 20oC and T = 600oC, are presented in the paper. The tests were performed under conditions of controlled deformation (εac = const) and controlled stress (σa = const). A comparative analysis of the test results showed that under conditions σa = const fatigue life is lower. Effect of load characteristics of fatigue is greater at temperature T=600oC.
Keywords: the fatigue characteristics of steel P91, effect of load characteristics, fatigue life
Maciej OLĘDZKI, Andrzej BŁASZCZYK, Mariusz NAWROCKI
Modernization of the 6RMY56 centrifugal compressor in the aspect of reducing its energy consumption and adjusting flow parameters to the network
The article presents the results of modernization of the 6RMY56 compressor produced by CKD, built at PGE GiEK S.A. Belchatow Power Plant. The scope of work included: adjustment of flow-energy parameters to the requirements of the compressed air installation; reducing energy consumption by limiting the amount of air blown into the atmosphere et replacement or repair of the construction-movement elements. Compressor after modernization realizes: higher volumetric flow rate, lower power than assumed. The scope and duration of the blow-out valve work has been limited to the minimum possible. As a result, the energy intensity factor decreased from 0,15368 kW/(mn3/h) to the value of 0,12621 kW/(mn3/h). The contractor for the modernization of the compressor was Przedsiębiorstwo Badawczo-Wdrożeniowe HYDRO-POMP Łódź.
Keywords: the 6RMY56 centrifugal compressor, modernization, P.B.W. HYDRO-POMP Łódź
Andrzej SITKA, Wojciech POSPOLITA, Daniel SMYKOWSKI, Janusz LICHOTA, Janusz POSPOLITA
Paraffin as heat accumulative material for PCM accumulator
Accumulation of thermal energy is one of the solutions to make energy systems more flexible, which is important for the rational use of energy. A heat accumulator implemented in an existing or new thermal system allows to improve its production dynamic, increase efficiency and reduce its negative impact on the environment. One of a very important problem is the choice of material to be used in the accumulator. The paper presents the results of research on the possibility of using paraffin as a heat accumulating material. Thermogravimetric analysis of material samples and measurements were carried out on a test stand equipped with a heat accumulator.
Keywords: a heat accumulator, paraffin as a heat accumulating material, the results of research on the possibility of using paraffin
Cezary STARCZEWSKI, Andrzej BŁASZCZYK, Mariusz NAWROCKI
Optimal steering of the inlet guide vanes in the modernized 160D30 cooling water pumps
The article presents the purpose, scope and effects of modernization of the 160D30 pumps implemented by the P.B.W. HYDRO-POMP. Optimal pump performance control required the development of an algorithm that, for a given load and a given block work variant, allows to determine the capacity of the cooling water pumps guaranteeing a suitable vacuum in the condenser of a 390 MW condenser turbine. Also electricity savings resulting from optimal control of the capacity by the inlet guide vanes built at the inlet of the 160D30 pumps were given for block number 12 of the Belchatow Power Plant.
Keywords: the 160D30 cooling water pumps, modernization, optimal steering of the inlet guide vanes
Zdzisław ŚLODERBACH
Bifurcation state during the adiabatic process of plastic deformations of metallic materials and state of low cycle (elastic-plastic) fatique
The adiabatic process of plastic deformation of metallic materials is analyzed in frames of coupled thermoplasticity theory. The critical value of plastic strains, critical temperature, critical values of stresses and the value of internal parameter identified with the plastic strain work are determined. The critical state determines the maximum of the adiabatic curve of hardening; in other words indicates when the adiabatic function (adiabatic modulus) of hardening reaches zero. Exceeding of the critical values can cause the forming of the localization state of deformations or initiation of microcracks during processes of adiabaticdeformations. Such phenomena can appear even under quasi-static and higher rates of plastic strain. The idea of macroscopic internal parameters was applied for description of thermodynamic state of the coupled thermoplastic body.
Keywords: adiabatic process of plastic deformations of metallic materials, bifurcation state, state of low cycle (elastic-plastic) fatique
Adam ZIELIŃSKI, Robert WERSTA
Structure of S304H steel after 10 000 hours of aging
S304H steel is used in the construction of pressure elements of boilers with supercritical operation parameters. The paper presents the results of microstructure testing after aging for 1000 and 10 000 hours at 650 and 700oC. Microstructure research was performed using scanning and transmission electron microscopy. Identification of precipitates occurring was carried out using transmission electron microscopy. The influence of aging time on microstructure changes and the precipitation process of the tested steel is described. The presented research results are an element of material characteristics of the new generation of steel, which are used in the design work of pressure devices of steam boilers and in diagnostic work during operation.
Keywords: structure of S304H steel after 10 000 hours of aging, microstructure testing, the influence of aging time on the precipitation process of the tested steel
Paweł ZIÓŁKOWSKI, Janusz BURACZEWSKI, Janusz BADUR
An overview of gas turbines adapted to the needs of the new combined cycle gas turbine in Gorzów Wielkopolski – in comparison to experience after the year
In the work, seven systems of gas turbines, namely: SGT-800; LSM100PB; MS6001FA; MS6001B; MS6001C; Trent60WLE and Trent 60DLE are compared. The following requirements were followed: the electric power of the new combined cycle gas turbine; thermal power of a new heat and power plant; differentiation of the combustion gas used in the burners to high-nitrogen and typical natural gas; meeting emission and pollution limits. Part of the work was done on the basis of the CFM tools that allow modeling cycles of gas-steam CHP plants in various work regimes, including winter and summer. Based on the performed analysis and operational experience, it should be stated that the turbine owner has made the right choice considering the heat and electricity demand for the city of Gorzów Wielkopolski.
Keywords: gas turbines, the new combined cycle gas turbine in Gorzów Wielkopolski, operational experience