Herbert Leopold GABRYŚ
Power industry in Poland. Selected production results achieved in the first half of 2011
Compiled and analysed are data concerning production and consumption of electric energy in the first half of 2011 in the Polish power sub-sector. Attention is paid to financial results in firms belonging to this sector as well as the participation in electricity production of electric power stations fired by hard coal, lignite or utilizing renewable energy sources. Critically assessed are the expected EU decisions concerning limits on CO2 emissions until the year 2050 and their negative impact on the whole of Polish economy.
Keywords: electric power industry, production results achieved by economic subjects in the first half of 2011, future of coal power industry
Ryszard BARTNIK, Anna DUCZKOWSKA-KĄDZIEL
The single and dual-fuel gas-steam technologies as a very important modernization potential of the domestic power industry
The single-fuel gas-steam combined-cycles power station and the so-called clean coal technologies based on gas turbines are a very important modernization potential of the domestic power industry. They are characterized by relatively high energy effectiveness and low emission of pollutants to the environment. They are, among the others, dual-fuel gas-and-steam technologies and coal-and-gas systems coupled in series or parallel. The coal-and-gas systems, what is really important, can be created by adding the gas turbine to the already existing coal structures. In practice, the parallel system is more energetically and economically effective method of a power plant modernization. The paper presents also the comparison of economic effectiveness of the 370 MW power block modernized to cogeneration work in a dual-fuel steam-gas system with the effectiveness of a single-fuel CHP station of the same heat output. This comparison is definitely for the power block’s disadvantage, as the specific heat production cost generated by the power block is higher than the one in a single-fuel steam-gas CHP station.
Keywords: modernization potential in power industry, steam and gas technologies, efficiency of mono- and dual-fuel power units
Marek CIEŚLA, Marek PLAZA
Creeping as the process of a tension member rupturing in the suspension of the 3rd stage superheater inlet chamber
Analysed are the reasons of a tension member rupturing in the suspension of the 3rd stage superheater inlet chamber in the atmosphere or hot flue gases leaking through the untight roof of an OP-230 boiler. Testing of metallurgical and mechanical properties of the tension member material as well as numerical effort analyses considering the empirically determined force in the suspension, lead to the conclusion that the main reason of the crack occurrence is the influence of high temperature on the tension member in the area of its constructional notch. This, in turn, results in degradation process intensification and damaging of the member material structure in the way of dislocation creeping and finally in the rupture of the tension member in the superheater chamber suspension.
Keywords: power boilers OP-230, superheater, rupturing of suspension tension members
Mirosław GAJEWSKI, Justyna KASIŃSKA, Leopold BARWICKI
Degradation of structure and boiler pipes damage from 13CrMo4-5 (15HM) steel
The work shows the results of the studies of pipe connecting middle chambers of steam superheater with escape chamber of OP140 boiler, which were destroyed as a result of long-term exploitation. The nature of exploitations failure were specified. It was found that the cause of these occurrence has advanced the degradation of 13CrMo4-5 (15HM) steel in the effect of working in supercritical parameters.
Keywords: power boilers OP-140, boiler tubes, damages and structure degradation
Krzysztof J. JESIONEK
Damage of centrifugal compressor of nitrogenous gas
The analysis of both operation conditions and causes of damages for centrifugal compressor type GHH has been performed. The turbocompressor is usually working with NOx gaseous mixture in nitric acid installation. Operating time of the new rotor was very short – 16 days only. Assessment of its suitability for existing conditions of operation was made in the paper.
Keywords: nitric acid turbine generator set, radial compressors, failures
Andrzej KUREK, Adam NIESŁONY
Fatigue strength of selected bimetallic material used in energy industry
The paper presents fatigue tests results of bimetal steel-clad titanium explosively welded. The study involved a sample made of bimetal which is a combination of steel S355J2 with titanium SB 265 G1, which was imposed in the process of material cladding
Keywords: electric power industry, bimetallic materials, fatigue life
Tadeusz ŁAGODA
Assessment of fatigue life of welded joints from to the nominal system to the fracture mechanic
The paper presents methods for fatigue life assessment of welded joints with special regard to typical joints. Possible methods for determination of calculated stresses in welded joints, ranging from nominal stresses according to various proposals through structural stresses, including hot-spot type to the use of linear fracture mechanics have been shown. On this background, recommendations of the International Welding Institute for fatigue life estimation of steel and aluminum welded joints under uniaxial tension-compression of flat elements have been discussed. Special attention is paid to determination and evaluation of fatigue life of some welded joints according to recommendations of IIW
Keywords: welded joints, fatigue life, determination methods
Jerzy OKRAJNI
Assessment of the influence of boiler operation conditions on the thermo-mechanical fatigue process
The main purpose of the work is the method of the description of the thermo-mechanical fatigue process of power plant components working under mechanical and thermal loading. The work focuses on the chosen component strain-stress characteristics. The FEM modelling has been used to describe the local stress-strain behaviour of the chosen power plant element. The calculations of stress and strain distribution on the component surface show that the internal pressure induces considerably smaller values of stresses and strains in comparison with the same stresses and strains specified for thermal loads. Thus, thermal impacts are responsible for cracks initiation and growth in areas of the greatest intensity of damage accumulation. The presented analysis is the part of the complex investigation method which main purpose is increasing the accuracy of the TMF process description and thermo-mechanical life assessment. In such situation investigations curried out in the work give the model approach and data for the comparison the real behaviour with the predictions.
Keywords: power boilers, boiler elements exploitation, thermo-mechanical fatigue
Radomir KACZMAREK, Aleksander A. STACHEL
Analysis of influence of vaporization temperatures in the middle and bottom cycle of power plant with three cycles on parameters its work
In this work was analysed influence of vaporization temperatures in the middle and in the bottom cycle of power plant with three cycles on power and efficiency of the power plant. In upper cycle this power plant as the working medium is used water, whereas in the middle and in the bottom cycle, is used low-boiling point fluid. Calculations were made for three condensation temperatures in the upper cycle and for three condensation temperatures in the middle cycle. Additionally, four low-boiling point fluids were concidered: isobutane and R236fa (in the middle cycle) and R227ea, RC318 (in the bottom cycle) as working medium. Obtained results were compared with results obtaining for basic power plant with water as a working medium, working in the same temperature range.
Keywords: three cycles power plant, evaporation temperature in power house circuits, low-boiling agents
Zdzisław ŚLODERBACH
Analysis of elastic-thermoplastic stresses in thick-walled pressure pipe. Part II. Discussion and Analysis of Obtained Results
The analysis is made on the example of analitycal solution of the thick-walled tube subjected to a quasistatically increasing internal pressure for the case of adiabatic processes ( without heat flow). Since the loading with internal pressure is quasi-static (monotonic), then neglecting a process of heat flow can lead to some different results in calculated stresses, deformations, temperature, internal pressure and residual stresses. The calculations for isothermal type of processes of deformations (without a heat or ideal cooling) are also performed for the estimation of these differences. The results calculated for the process with heat flow should be intermediate between the values obtained for isothermal and adiabatic processes. The results of calculations are presented in the form of appropriate diagrams and in the table.
Keywords: thick-walled pressure pipes, adiabatic processes, elastic-plastic stress
Sławomir WIŚNIEWSKI
Analysis of work of orc system coupled with gas turbine with the use of exhaust gases circulation
This paper concerns the use of the waste thermal energy contained in exhaust gases leaving the gas turbine layout. In paper has been presented the analysis of work of low power gas turbine arrangement thermally coupled with ORC system (Organic Rankine Cycle). The analysis showed, that the use of additional ORC system increases the electric power produced in the system. In the proposed solution, is used circulation of exhaust gases leaving gas turbine in order to reduce their temperature. In the particular parts of the work are described the scheme of installation, parameters of work of gas turbine and ORC system, calculation method, exemplary analysis results and final conclusions.
Keywords: waste energy utilization, gas turbine, flue gas circulation
Anżelina MAREK, Jerzy OKRAJNI
Characteristics of a power unit main steam valve body fatigue process
Presented is one of the many examples of computer modelling methods application for evaluation of the variable in time temperature and stress fields in power installations. Discussed is the problem of determining stress patterns in elements of thick-walled power pipelines in transient working conditions during a power unit start-up. There is proved a possibility to use measurements of steam temperature and the temperature of selected points of the investigated elements for defining boundary conditions of the heat transfer modelling problem as well as to verify operative correctness of the elaborated computer models. Shown is essential importance of time-variable and non-uniform temperature field for the course of local stress changes that results in metal fatigue processes.
Keywords: power units, steam valves, fatigue processes
Waldemar SKOMUDEK, Jan SUBOCZ, Marek SZROT
Assessment of technical condition of high voltage studs type insulators of power transformers (Part 2)
In recent years the power sector recorded an increased failure rate bushings of power transformers. These failures, which often lead to serious damage or even destroy the transformer. The main reason for their formation is the development of aging processes of isolation. The paper presents selected information on the new test method to evaluate the impact of aging on the reliability of the isolation condenser bushings. The paper pointed out the need to develop diagnostic methods to enable reliable assessment of the technical condition of insulators investigated, based primarily on the identification of the initial phase of the development aging process possible to identify the active transformer. (Assessment of technical condition of high voltage studs type insulators of power transformers – part 2).
Keywords: transformers, bushing insulators, ageing of insulation, evaluation of technical condition
Artur JASIŃSKI
Complex evaluation of technical condition of long-operated power units installations as a starting point for their further operation
In the situation of limited investment resources for reconstruction of Polish power industry, a good knowledge of a real technical condition of the working power units installations is needed. Discussed are proposals concerning the range of required diagnostic tests and analyses necessary for evaluation of the possible future long-term units operation. Identyfied are criterial elements limiting operational life. Presented are input data for operational life analyses for individual groups of appliances. Attention is paid to the influence of biomass co-combustion on the lifespan of some unit elements. Proposed tests, analyses and evaluation of installations make the ground for undertaking necessary overhaul actions with the aim to prolong their operational life and, at the same time,of the unit as a whole.
Keywords: power units, diagnostic tests, increase of installations operational life
Artur JASIŃSKI, Michał KWIECIEŃ
Durability of superheater pipe-coils and boiler water-walls in the perspective of their futher operation in conditions of biomass co-combustion
The quality of medium circulating in a water/steam circuit and combustion conditions in the boiler have an essential impact on durability and operational usefulness of conventional coal-dust boilers heating surfaces. Discussed are the possible causes of rapid wear-out and damages of heating surfaces pipes, including the cases of biomass co-combustion in a boiler. Presented is a proposal to carry out multiple pipe diagnostics and to monitor effects of the corrosion-erosion occurrences i.e. of the progressing pipe degradation. Multiple diagnostics and monitoring will allow the optimum planning of worn out pipes replacement, prolonging operational life and increasing the boiler availability.
Keywords: superheater pipe-coils, boiler water-walls, biomass co-combustion
Artur JASIŃSKI, Tomasz ZACZKIEWICZ
Diagnostics of the mounting system of pipelines working in a steam distribution header
Attention is paid to specific working conditions of the mounting system of pipelines working in a steam distribution header. Described is the required range of tests and analyses of the condition and functioning of mounting systems of high pressure steam pipelines. Presented are the applied measuring methods of various mountings characteristic parameters. Emphasized is the importance of the proper testing results interpretation and given are examples taken from research practice. Discussed are long term advantages coming from the correct and regular mounting system diagnostics.
Keywords: steam pipelines, mounting system diagnostics, steam distribution header
Grzegorz DĄBROWSKI
Maintenance of power installations during planned outages
The outage of a power unit for an overhaul or modernization, needs taking actions leading to reduction of corrosion processes during the standstill. Especially, very important are operations aiming at the effective protection of the inner surface of a water-steam system in a boiler. Discussed is the mechanism of standstill corrosion, factors influencing corrosion process dynamics, characteristic damages and corrosion products. Presented are various methods of boiler protection with special recommendation for the ones with the use of compressed air or an inert gas.
Keywords: power installations, standstill corrosion, boiler corrosion protection methods
Artur JASIŃSKI
“ENERGOPOMIAR” Sp. z o.o. experience in diagnostic testing of steam boiler drums
Discussed is the range of diagnostic testing, calculations and analyses carried out with the aim to determine the technical condition of a boiler drum and to forecast possibilities of its further operation. Presented are processes of boiler drum destruction during operation, typical damages and methods of their repairs. Mentioned are problems connected with evaluation of a boiler drum operational life and its material structural changes. The elaborated for many years methodology of complex diagnostics has given results in the form of improving operational reliability and extending lifetime of boiler drums.
Keywords: steam boiler drums, diagnostic testing in “ENERGOPOMIAR” Sp. z o.o.