Krzysztof BADYDA, Michał KUŹNIEWSKI
Economic viability analysis of a nuclear power plant construction in Poland
A nuclear plant construction in conditions of energy sales at expected prices at a stock exchange has no economic justification. The project will for sure need the State’s support and that support will probably be similar to the mechanism of the British Contracts for Difference. Power market implementation and a big rise in carbon certificates’ prices as the result of European Comission activities can also have positive impact on the project profitability. The need to support a nuclear plant construction results from such a plant’s strategic position in power systems of states that already have nuclear power stations and a significant role in meeting requirements concerning decarbonization of the EU member states’ economies. A significant advantage are also considerably lower the so-called external costs of electric energy generation from nuclear sources than from the coal ones. The support, in the form of a guaranteed electric energy price on the level of 300 zł/MWh, is able to ensure the project’s profitability with the adopted investment financing model. The vast majority of a nuclear plant electric energy cost is a very high capital expenditure that in turn entails a high investment risk. The return on such an investment is practically not liable to changes in variable costs relative to the base scenario.
Keywords: nuclear plants profitability, types of a nuclear plant construction support, external costs
Sławomir BIELECKI
The problem of settlements for reactive power utilization
The reactive power is a technical term characterizing alternative current circuits and having no direct equivalent in mechanics. The presence of power and energy of a reactive character is necessary for proper functioning of many energy receivers. Reactive power is also a factor having influence on proper operation of networks and power systems and, like active power, should be balanced on an ongoing basis.Transmission of reactive power can cause negative effects causing particularly reduction of efficiency (energy efficiency) of energy supply to endusers and is reflected in provisions included in the current national legislation concerning energy efficiency (Energy Efficiency Improvement Act). But the problem of proper fees formation for reactive power utilization as well as conducting of clearing of accounts for generation and consumption of power and reactive energy in power systems seems to be unsolved so far. It is indicated by criticisms expressed about the presently used clearing methods that are different in various countries, various ideas of fees shaping and, what is more, various concepts concerning the definition of the term „reactive power” itself. Presented are here selected problems relating to clearing of accounts for reactive power utilization and a review of the presently used methods and new proposals. Special attention is called to the necessity of making a complex arrangement of this issue, especially in the context of intelligent networks implementation and development of prosumer installations, creation of competitive energy market, current problems related to energy efficiency improvement and electric energy rational management.
Keywords: energy efficiency, reactive power, clearing of accounts for reactive power generation and consumption
Janusz KOTOWICZ, Marcin JOB, Mateusz BRZĘCZEK
A comparison of different structures of a technologically advanced zero-emission combined cycle power plant
The advanced zero-emission combined cycle power plants (AZEP) are based on a technology enabling electric energy production from natural gas with a zero carbon dioxide emission and a high efficiency. The efficiency loss related to a modern natural gas combined cycle plant without CO2 capture installation is even lower than 5 percentage points. This concept is based on the use of a membrane reactor replacing the combustor in the gas turbine. The reactor combines three key functions: oxygen separation from air through the high-temperature membrane, fuel combustion in an internal reactor cycle and heating of the oxygen-depleted air. The hot air expands in the turbine and subsequently feeds the steam cycle through a heat recovery steam generator. The membrane reactor can operate on a low or a higher pressure level. In the first case the flue gas leaving reactor feeds an additional heat recovery steam generator, while in the second case it is possible to apply an additional turbine powered by flue gas. Carbon dioxide separation from the flue gas, composed almost entirely of H2O and CO2, is limited to the flue gas cooling and condensation of water vapor. Presented are various structures and results of thermodynamic analyses of natural gas combined cycle plants integrated with membrane reactors.
Keywords: combined cycle power plants, zero-emission power plants, CO2 capture, oxygen combustion, membrane reactor
Tomasz KRESS, Izabella MAJ, Agata MLONKA-MĘDRALA, Marek PRONOBIS
Recommendations regarding biomass-fired boilers designing with a view to reduce chlorine corrosion and a boiler heating surfaces contamination
Discussed is the problem of a boiler heating surfaces high-temperature corrosion occurring during combustion of biomass containing chlorine. Presented are verified formulae to calculate corrosion rate of boiling tubes and a biomass boiler superheater as well as the results of exemplary calculations. Proved is that addition of aluminosilicates to fuels fed to a furnace can result in releasing of chlorine from chlorides before they reach heating surfaces that in turn becomes an effective means of corrosion prevention. For the assessment of differences between the composition and properties of the flying ash and the sediment formed on surfaces of a high-temperature stages of a biomass boiler superheater, a research was performed with the use of an IMiUE dust test chamber. Tests showed that the settling process on the probe (in conditions compatible with those in which a superheater works) has a selctive character and prefers substances of lower than the fly ash characteristic temperatures so it can result in superheater slagging. At the same time a considerable bigger participation of potassium, chlorides, sulphur and phosphor can be observed that significantly increases the corrosion hazard. On the basis of these tests and calculations the constructional and operational recommendations were elaborated with a view to reduce the chlorine corrosion and a boiler heating surfaces contamination.
Keywords: biomass-fired boilers, corrosion of biomass boilers boiling tubes and superheaters, constructional and operational recommendations
Władysław KRYŁŁOWICZ, Stanisław SZWAJA, Grzegorz LIŚKIEWICZ
Design of a small Electra type steam turbine for a distributed power generation
Described is the construction of a prototype small steam turbine dedicated to co-operate with a stationary biogas-fuelled combustion engine. Discussed are main principles that contributed to a selection of the flow system (two-stage Electra turbine) and presented is the construction of basic subassemblies. Contained are conclusions concerning the experience gained during designing and construction of the prototype.
Keywords: small steam turbine, gas-fuelled combustion engine, flow system
Karol MAJEWSKI, Sławomir GRZĄDZIEL
Modeling of flow and thermal phenomena in smooth and inner finned tubes
Proposed is modeling of flow and thermal phenomena occurring in smooth and inner finned tubes. The model is based on solving balancing equations describing rules concerning mass, momentum and energy conservation that enable analysis of transient processes. It is a model of distributed parameters. The purpose to make those calculations is i.a. determination of enthalpy distribution, mass stream, pressure of medium inside smooth and inner finned tubes and the heat transfer coefficient. The analysis was performed for vertical system tubes working in supercritical steam parameters. The results obtained in the way of numerical computations will be compared to the ones obtained with the help of CFD modeling.
Keywords: supercritical boiler, smooth tubes, inner finned tubes, equations of mass, momentum and energy conservation, heat load
Wojciech OLSZEWSKI, Marek DZIDA
Electric energy production in economic terms
Presented are basic dependences concerning technical and economic analyses relating to investment projects. A combined system is shown – a Diesel engine and a steam turbine – and its task, because it is mounted on a floating platform, is production of electric energy in the so-called distributed system. It consists of a reciprocating combustion engine and an associated steam turbine system using energy contained in the engine flue-gases. Described are assumptions and limitations as well as calculation results. Determined is the electric energy generation level dependent on the working power units. Calculations were made only from the point of view of investment costs and further operation. The analysis was performed with the use of slow speed motors produced by Wartsila and MAN Diesel&Turbo of around 54 MW total capacity and on that basis the estimated generation cost of 1 MWh of electric energy was calculated.
Keywords: electric energy, Diesel engine, steam turbine, floating electric power plant
Antoni SALIJ
Operational problems and modernization effects of turbines working in 225 MW steam power units
Presented are basic thermal tests of steam turbines including the ones performed after the modernization. Discussed are aims and methodology of realization of these tests. As an example, the technical scope of a 225 MW power unit steam turbine modernization is shown. The comparison between turbine construction elements (replacement of components) before and after the modernization is graphically depicted. Discussed are selected technical problems occurring during commissioning and further operation of modernized turbines together with recommendations for operation and maintenance services concerning methods with which they can be dealt with. Modernization effects of 225 MW power unit steam turbines are presented with the help of showing their basic parameters as well as the technical and economic indicators.
Keywords: steam turbines, modernization, commissioning and operation of modernized turbines
Karol SZTEKLER, Maciej KOMOROWSKI, Kamil WAL
Modeling of reduction process of CO2 emission from power plants
According to the International Energy Agency (IEA) the CO2 world’s emission in 2013 was equal to 35,1 billion tons i.e. 670 mln tons of CO2 more than in 2012. On the basis of available data China is still the largest CO2 emitter with their 9,5 billion tons, then the USA – 5,9 billion, India – 1,9 billion and Russia – 1,7 billion. Poland is responsible for emitting in the year 2013 around 290 mln tons i.e. 0,3% more in comparison with the 2012. IEA is predicting that until the year 2030 the CO2 world’s emission can increase by 45%. This is mainly caused by the growth of electric energy consumption in developing countries that want to catch up in economic terms with the most developed ones. Attention should be paid to the fact that processes connected with electric energy generation are responsible for up to 40% of the CO2 world’s emission. Power industry in Poland is also based on coal and so 84% of energy produced in the year 2013 came from coal combustion while only 3,2% from gas fuels. Currently, the CO2 capture installations are not operating at the full-scale. One of the methods to determine the impact of a CO2 capture system on the operation of coal-fired power plants before industrial installations are built is to model a separation unit in a development environment and to configure it to work as effective as possbile. For the simulation analysis the IPSEpro software was used that helped to model a reference cycle for a coal-fired power plant for supercritical parameters and the CO2 separation system. The separation unit is based on adsorbtion methods (post-combustion) and in the present case analysed were PSA (Pressure Swing Adsorption) and TSA (Temperature Swing Adsorption) as well as PTSA (Pressure Temperature Swing Adsorption) separation technologies with the use of zeolite adsorbents (natural, synthetic and synthesized from fly-ash) for the capture. After the systems had been elaborated, a CO2 separation unit was put into operation and integrated – together with appliances necessary to realize the process – with the power plant water and steam circuit. Data obtained from computer simulations would then enable the analysis of the impact of a CO2 separation unit and of other installations (needed for realization of the CO2 capture process and further preparation of the gas for transportation in the liquid form) on a power unit operation.
Keywords: CO2 emission, modeling of separation units, liquid CO2 transportation
Jerzy TRZESZCZYŃSKI
Using the failure analysis to increase the accuracy of lifetime prediction of heating surface tubes and to improve boilers’ availability
Damages of heating surface tubes in steam boilers have the greatest impact on availability of power units. They lead to the loss of production and are a source of repair costs and failure recovery. But failure is also a possible source of information and knowledge, which may be used to improve the quality of assessment and lifetime prediction. In the paper there is shown such kind of attitude, which – when supported by proper software – may be particularly attractive for extending the lifetime of power units directed to operation in cycle load.
Keywords: steam boilers, damages of heating surface tubes in steam boilers
Michał BӦHM, Artur DZIURA, Adam NIESŁONY
Taking into account the influence of the elastic-plastic deformations on the calculated fatigue life determined by means of the Spectral Method
The paper presents the theoretical assumptions behind the solution of the problem with taking into account the influence of the local elastic-plastic deformations on the calculated fatigue life using the spectral method for fatigue life assessment. The topic is interesting for the energy production industry due to the large amount of geometrical and construction notches occurring in the power plant constructions. The main formulas and algorithm modification are presented.
Keywords: elastic-plastic deformations, the spectral method
Janusz DOBRZAŃSKI, Hanna PURZYŃSKA, Mirosław MATUSIK
Materials testing in the assessment of condition and forecasting about further safe service of steam turbine rotors beyond the design service life
The paper presents: selected results of non-destructive and destructive materials testing of 23H2MF steel turbin rotors after service much beyond 200 thousand hours; methodology for evaluation of TK-120 turbine shaft microstructure by non-destructive matrix replica method based on the example of its HP part and assignment of exhaustion degree to it; selected results of non-destructive testing of the HP part of TK-200 turbine shaft; microstructure, phase composition of carbides, mechanical properties, nil ductility transition temperature and abridged creep tests; determination of residual life and disposable residual life.
Keywords: steam turbine rotors, TK-120 turbine shaft
Marek JAWORSKI, Dariusz MĘŻYK
Magnetic method of the measurement of the installation of energy pipelines
Barkhausen effect measurements allow to determine changes in the level of stress in the material with an accuracy of a few percent, the absolute error values indicated stress is greater than the method of strain gauges, primarily because of the possible differences between the model and the test material. The results allow to conclude that the use of the Barkhausen effect to evaluate the stresses in structures such as thick-walled pipe pressure systems is fully enforceable. It is advantageous to carry out a major series of studies on various materials using both methods in order to develop a method for measuring the full repeatability of the results of stress testing of pipelines operating at different load conditions.
Keywords: energy pipelines, the Barkhausen effect, magnetic method of the measurement
Andrzej KUREK, Tadeusz ŁAGODA, Anna KULESA, Marta KUREK
Fatigue life prediction for 15Mo3 steel at elevated temperatures
The paper presents the results of fatigue tests of steel 15Mo3 carried out in six different temperatures, from 23 to 500°C. Next, by using various types of strain-life curve models the results were confronted with Ross model which accounts for the effect of test temperature on the fatigue properties of the material.
Keywords: 15Mo3 steel, fatigue tests
Andrzej BŁASZCZYK, Adam PAPIERSKI, Mariusz SUSIK, Grzegorz KOŹBA, Mariusz NAWROCKI, Dariusz WOŹNIAK
Modernization of pumps in power industry (examples)
Described are selected examples of modernization of pumps working in the power industry. The exemplary modernizations were performed with the aim to improve operating conditions, to adjust flow parameters of pumps to the requirements of technological processes and to increase durability and reliability of pumps as well as their efficiency and flow parameters like capacity and pump delivery.
Keywords: power industry pumps, pump modernization