Steam Turbine Plant Research Articles

Conceptual Design of Small NPP with RITM-200 Reactor

A small ground-based nuclear power plant with two RITM-200 reactors is examined. The plant is intended for electric and thermal energy production and desalination of water. The general layout of the site, arrangement of the basic engineering and technical structures, characteristics of the reactor and steam turbine plants, and systems and equipment of the power plant are examined. RITM-200 is used in the universal nuclear icebreakers now under construction. Its compactness and capacity for operating in a maneuvering regime, flexibly following the required power, makes it possible to attain high technical and economic performance and plant efficiency. The design of a power plant with RITM-200 complies with the current global requirements and trends in the field of safety of nuclear power plants. The requisite number of active and passive safety systems are provided for this purpose. Optimization R&D to improve the technical and economic characteristics of the plant and increase its commercial attractiveness is to be performed at later stages of the design process.

Exploitation of Empty Palm Fruit Bunch for the Generation of Electricity

Electricity is very important for the growth and economy of a country. Biomass wastes such as waste from oil palm plantation companies can be harnessed for this purpose since they are usually abundant in nature. The aim of this study is to evaluate the utilization of empty palm fruit bunch for the generation of electricity. The empty fruit bunch (EFB) was used in firing a steam turbine plant (boiler) for the generation of electricity. The power plant that was used in this research is owned by PRESCO Nigeria Limited located in Ikpoba-Okha local government area of Edo state. 1.7 MW of electricity was generated by burning empty fruit bunch (EFB) at a rate of 896 kg/h when the steam boiler was used. This value was compared with the traditional power plant fired using methane gas which produces 4.5MW. This value (1.7 MW) shows that EFB is a very good alternative for firing a boiler plant, power generation and elimination of wastes.

Water Quality Control for Steam Turbine Plants on LNGC - Comparison of Boiler Water Conditioning for 10MPa and 6MPa Steam Turbine Plants

Water Quality Control for Steam Turbine Plants on LNGC - Comparison of Boiler Water Conditioning for 10MPa and 6MPa Steam Turbine Plants

Condition Based Maintenance Program for Combined Cycle Power Plant

Combined cycle power plant plays an important role to generate electricity in an efficient way. The greater efficiency achievement is due to the reason that the exhaust heat energy from the gas turbine units is being utilized to produce steam for the steam turbine units. It is also true that the entire mechanical system becomes more complex than that of a single gas turbine or steam turbine plant. Therefore, it necessitates taking care of this complex system properly so that availability of the plant can be achieved to a great extent. This availability is closely related to the maintenance activity of the plant. Since preventive maintenance policy incurred significant involvement of cost, it justifies going for condition-based maintenance (CBM). Prognostic and diagnostic are the main two aspects of CBM. Prognostic is more important than diagnostic as prognostic can show the trend of abnormality inside the equipment of the plant. However, diagnostic is also important if abnormality has already been achieved. Based on this requirement, the present work has been chosen where condition monitoring has been performed for a combined cycle power plant. Used lubricating oils have been collected from the different units of the plant at a regular interval for three years and the collected samples have been experimented to investigate of wear rate of the equipment. Ferrographic technique has been applied to examine wear situation. Results indicate that it is required to implement CBM policy for the plant.

Make-up Water Heating Capability, Conditions, and Efficiency in Built in Bundles when Cooling Water Is Concurrently Piped through the Main Condenser Bundles

The paper considers the make-up water heating capability and conditions in the built-in tube bundles when cooling water is concurrently piped through the main turbine condenser bundles. Based on the analysis of experimental and calculated data, a technique is proposed for estimating heat fluxes entering the condenser when the turbine plant operates in the heat production mode. It is shown that, for efficient operation of the built-in bundle as part of the condensing system, all heat fluxes coming in addition to the wheelspace should be directed into the regenerative heating zone under the built-in condenser bundles through special water distribution devices, and the inlet zone itself should be separated from the condenser chamber by enclosing shields. The calculation studies were carried out using a mathematical condenser model of a cogeneration steam turbine plant with built-in condenser bundles. The studies were performed on the model of a turbine plant T-50-12.8 for three seal levels of the low-pressure sliding grid and different make-up water flows and temperatures. The conducted researches made it possible to determine the heat distribution in the condenser between the condenser bundles in different turbine operating modes and to reveal the absence of pressure constraints in the condenser and make-up water temperature constraints at the outlet of the built-in bundle. Based on the turbine plant T-50-12.8 mathematical model, thermal efficiency calculations were performed using the built-in make-up water condenser bundles when the main bundles operate in the cooling mode. It is shown that the heat economy of the turbine plant operating in the considered regimes in the heat production mode with the make-up water flows close to the nominal make up 70% and more of the condenser heat load.

Thermal Power Plant Steam Turbine Output Operational Characteristics Change Probabilistic Model Driven by the Second Derivation Control Actions

The subject of the research is thermal station power equipment, in particular steam turbines and steam turbine plant support equipment. In the modern context, when working lifespan of the power equipment outreached the limit, thus the goal is to assure it performance and availability for producing enough energy and heat. To reach the goal it’s necessary to design and implement the probabilistic models and techniques for power equipment reliability under present day conditions. The probabilistic second derivative output parameters change model of power equipment is first developed by the authors and is the scientific novelty of the research. In the paper the assumptions and suppostitions on which the model is based are described. The practical implication of the model consists of capability of rational maintenance and repair operation term estimation of thermal power plant steam turbines. The model is based on the mathematical statistics methods, probability theory and matrix calculus. The probabilistic model allows forecasting the output characteristics change in time and control actions explicitly. The example of output characteristics change for long term utilization is given. During the research the statistical power equipment elements failure and error material has been acquired and presented in relative failure and error share diagram. The internal and external technical and operational factors influencing the failure statistics are determined. For quantitive reliability estimation of power equipment the set of primary indices, influencing turbine performance and reliability, is presented.

The potential for reducing TPP water consumption through the use of heat pumps

Largest part of consumed water resources in Russian Federation is related to energy sector; accordingly, we need to develop measures to ensure their rational use. This paper analyzes the potential for reducing water consumption of thermal power plants by applying heat pumps in the condenser cooling system of a steam turbine plant. The calculations were performed for two CCGT-450 power units with three main options for technical water supply systems. The greatest environmental and economic effects are provided by the use of heat pumps at TPPs with a once-through water supply system. Utilization of all low-grade heat of the condenser cooling system of a steam turbine plant is irrational due to an increase in energy consumption for TPP own needs. With a further growth of tax rates for water intake from surface water bodies, positive effect of application of heat pumps in the condenser cooling system of a steam turbine plant will increase by an order of magnitude.

An Automated Flow Traversing Measurement System in the Last Stages of Large-Capacity Steam Turbines

The article presents the results from putting a new automated flow traversing measurement system (AFTMS) in an experimental turbine intended for testing steam paths of the low-pressure cylinders (LPC) of large-capacity steam turbines into use. Modern computerized facilities have been used in developing the system. Such an approach has been implemented for the first time in the full-scale test bench available at PJSC Power Machines in carrying out experimental investigations of an LPC double stage compartment (on a 1 : 1 scale) equipped with a new, ultimately long last stage blade (LSB) developed for a steam turbine plant for ultrasupercritical steam conditions. The investigations were aimed at confirming the effectiveness of the developed system in measuring the flow parameters in the last LPC stage. The necessity of making a shift from nonautomated and semiautomatic systems to the use of automated measurement systems is substantiated. The article describes a system that makes it possible, with automated setting of the gas dynamic probe head position on the traversing line, to determine the steam flow direction; to measure the stagnation pressure, static pressure, and stagnation temperature; and to record the measures indicators with exactly assigned time tags. The results from measurements of flow parameters upstream of the last LPC stage in a partial load mode are given. A comparison between the experimental and calculated flow parameter distribution data over the stage radius in the control section is shown.

Comparative evaluation of different combined cycle configurations having simple gas turbine, steam turbine and ammonia water turbine

Gas/steam combined cycles have been increasingly used in power plants due to better energy utilization for getting better performance from them as compared to Brayton cycle based gas turbine plant or the Rankine cycle based steam turbine plant individually. However, there exists ample scope for further improvement in the performance of combined cycles through variations in their arrangements. The present study deals with the thermodynamic analysis of different combined cycle power plant configurations having the simple gas turbine with closed loop cooling of gas turbine blades and varying arrangements in the bottoming cycle. The variation in the bottoming cycle relies upon the effective utilization of energy available in the topping cycle. The bottoming cycle considered uses steam cycle or ammonia water cycle or its combination. The comparison of eight different combined cycle configurations considered in this study reveals that, the work output is maximum for simple gas turbine with bottoming cycle having reheat ammonia water turbine and steam turbine, with an output of 638 kJ/kg of air, first and second law efficiency of 54.95% and 57.87% respectively for ammonia mass fraction of 0.7. The exergy loss is found to be maximum for the combustion chamber followed by heat recovery vapor generator.

Research of the efficiency of combining nuclear power plants with a multifunctional autonomous hydrogen energy complex

Combining of the nuclear power plant power unit with an autonomous hydrogen complex including a low-power steam-turbine is proposed. This autonomous hydrogen complex makes it possible to increase the power and manoeuvring capabilities of the nuclear power unit, and in case of complete power blackout, provide power supply for own needs for more than 72 hours (IAEA requirement) due the energy of the residual heat release of the reactor. Hydrogen and oxygen can be generated by electrolysis of water at the expense of cheap off-peak energy of nuclear power units at night, after that it is effectively used in the daytime to generate steam, which is sent to a low-power steam turbine. The article evaluates the economic efficiency of the proposed system under conditions of uneven electric load schedule. It is shown that the proposed variant of combining nuclear power units with an autonomous hydrogen complex, including a low-power steam-turbine plant, makes it possible to improve the reliability of power supply for NPP’s own needs in emergency situations with blackout. This will, together with the additional benefit from the sale of peak electricity, significantly increase the competitiveness of nuclear power plants.

Experimental Studies of Honeycomb Seals with Wavy Ridges on the Rotor

During steam turbine operation in transient modes, contact in labyrinth seals is possible. To avoid such contact in the regular stepped labyrinth seals, specialists of the Ural Turbine Works upgraded the end seals during major repairs in several T-250/300-23.5 type turbines of PAO Mosenergo: the regular seals on the rotor were replaced by straight-flow honeycomb seals with wavy ridges. After this upgrading, there were a reduction of air suctions through the end seals of low-pressure cylinder, the normalization of the ejector operation, and oil watering reducing. However, by these indirect indices, it is impossible to evaluate the actual change of leakages through upgraded seals. Therefore, the comparative experimental studies of flow and dynamic characteristics of the straight-flow seals with classic straight and wavy ridges were implemented. According to the investigation results, the flow characteristics of all studied models of straight-flow seals during transition from classical straight ridges to wavy ones deteriorated. The measurements of nonconservative components of the force in the seal models also revealed a deterioration of dynamic characteristics of the models of straight-flow seals during transition from straight ridges to wavy ones. In the end seals, increasing the nonconservative forces capable to cause a self-excited vibration of the shafting of the steam-turbine plant (STP) does not pose a threat owing to their low magnitude. However, in diaphragm seals, especially in the high-pressure section of STP to the supercritical steam parameters, using new honeycomb straight-flow seals with wavy ridges requires special caution, since these forces reach the highest values in the region of high pressures and are capable, in combination with the overbandage forces and forces arising in the oil layer of bearings, to cause low-frequency self-excited vibrations of shaftings. Taking into account that the level of nonconservative forces in the regular stepped seals is by 20% less than in the straight-flow seals, the transition to the straight-flow honeycomb seals with wavy ridges on the rotor in the diaphragm seals appears inappropriate.

Simulation models for supporting the solar thermal power plant operator

The benefits that may accrue for the operators of Solar Thermal Power Plants by integrating simulators to everyday operation and maintenance management is demonstrated by using a simulation environment allowing steady state and transient modelling. Two representative STPPs are used as test cases, namely a hybrid solar gas turbine plant and a solar steam turbine plant. The plants operation is simulated for different operating modes utilizing annual meteorological data. Component faults that may occur during operation, such as mirror soiling and misalignment are studied. The effects of different operating modes on performance and operability are established and evaluated. The effect of components degradation on performance is assessed, the overall plant performance deterioration is quantified, and the possibility for selecting optimal maintenance planning is discussed.

Investigating the efficiency of a steam-turbine heating plant with a back-pressure steam turbine and waste-heat recovery

The article considers a promising steam-turbine heating plant, which includes a steam turbine with back pressure and a steam boiler operating on natural gas, with waste heat recovery. The mathematical model of а steam-turbine heating plant has been developed to perform one design calculation in the nominal mode and several verification calculations in characteristic modes with different thermal loads. Optimization calculations of the unit were carried out for two regions with different climatic conditions and different fuel prices. The optimal design parameters of the equipment, the parameters of the working fluid and coolants at all points of the technological scheme, as well as fuel costs in each characteristic mode of operation have been found by the criterion of the minimum price of electricity. The considered steam-turbine heating plant provides a higher heat utilization coefficient of the fuel than the traditional heating plant.

Having CHPP involved in frequency control related to starting Belarusian NPP

The policy of restructuring the generating capacities of the energy system of the Republic of Belarus assumes the introduction of the the Belarusian nuclear power plant (NPP) in the coming years. The presence of external and internal factors affecting the sale of electricity from NPP will require solving a number of problems, including power redundancy and frequency control through involvement of internal power generating facilities. These include steam-turbine state power plants and combined heat and power plants (CHPP), combined-cycle power units, special mobile electric power units, the commissioning of electric boilers and accumulator tanks. The latter is a new technical solution for the Belarusian energy system that requires careful analysis to identify the optimal system for coordinated operation of co-generation power units with electric boilers and accumulator tanks. At the same time, the heating and non-heating seasons of the CHPP operation are considered. The function of the accumulator tanks with minimum and maximum power consumption is shown. At charging of the accumulator tanks, the generation of electricity by co-generation power units with thermal regulation is increased. The operation of electric boilers and accumulator tanks is considered through the example of Grodno CHPP-2. The expediency of including electric boilers in the scheme of the CHPP as the most effective means of using co-generation turbine units in the cycling mode with unloading them by electric power during the night hours is determined, which ensures the maximum reduction of the electric power output to the power system from the Belarusian NPP.A similar approach at other industrial CHPP of the power system will, to some extent, ensure stable power supply from the Belarusian NPP. Reconstruction of the CHPP with installation of accumulator tanks will make it possible to create a flexible heat supply scheme for consumers in the conditions of night electrical unloading when the NPP power units are put into operation.

The Study of Variational Feed Rate in 4-Axis Machining of Blades

As a core part of aerospace, space, and steam turbine plants, blades are generally machined via 5-axis linkage processing to satisfy the high precision requirements of the rigorous surface. To save costs in blade machining, many small- and medium-sized enterprises often combine standard 3-axis computer numeric control machines with the automatic indexing turntable. The traditional 4-axis machining method adopts a constant feed rate, which causes overcutting near the leading and trailing edges of the blade because of the rapid changes in tool orientation. To solve this problem, we propose a speed optimization method that utilizes variational speed to ensure that the decomposition velocity and acceleration of each axis do not exceed the allowable values. First, we guarantee the correct tool lead angle. Second, a corrected speed model is established to obtain the component speed of each axis and to determine the constraint conditions of maximum and accelerated speed. Third, a 4-axis post processor for blade processing is developed using Java advanced language combined with the optimization algorithm. The cutting experiment reveals that our proposed speed optimization method effectively controls the precision of the surface profile and overcomes the overcut phenomenon that often occurs in traditional 4-axis machining.

HYDROGEN-OXYGEN STEAM GENERATOR FOR A CLOSED HYDROGEN COMBUSTION CYCLE

The paper analyzes the problems of combustion hydrogen in an oxygen medium for produce high-temperature steam that can be used to produce electricity at various power plants. For example, at the nuclear power plants, the use of a H2-O2 steam generator as part of a hydrogen energy complex makes it possible to increase its power and efficiency in the operational mode due to steam-hydrogen overheating of the main working fluid of a steam-turbine plant. In addition, the use of the hydrogen energy complex makes it possible to adapt the nuclear power plants to variable electric load schedules in conditions of increasing the share of nuclear power plants and to develop environmentally friendly technologies for the production of electricity. The paper considers a new solution of the problem of effective and safe use of hydrogen energy at NPPs with a hydrogen energy complex.Technical solutions for the combustion of hydrogen in the oxygen medium using direct injection of cooling water or steam in the combustion products have a significant drawback – the effect of “quenching” when injecting water or water vapor which leads to a decrease in the efficiency of recombination during cooling of combustion products that is expressed in an increase fraction of non-condensable gases. In this case, the supply of such a mixture to the steam cycle is unsafe, because this can lead to a dangerous increase in the concentration of unburned hydrogen in the flowing part of the steam turbine plant. In order to solve this problem, the authors have proposed a closed hydrogen cycle and a hydrogen vapor overheating system based on it, and carried out a study of a closed hydrogen combustion system which completely eliminates hydrogen from entering the working fluid of the steam cycle and ensures its complete oxidation due to some excess of circulating oxygen.The paper considers two types of hydrogen-oxygen combustion chambers for the system of safe generating of superheated steam using hydrogen in nuclear power plant cycle by using a closed system for burning hydrogen in an oxygen medium. As a result of mathematical modeling of combustion processes and heat and mass transfer, we have determined the required parameters of a hydrogen-oxygen steam generator taking into account the temperature regime of its operation, and a power range of hydrogen-oxygen steam generators with the proposed combustion chamber design.

Efficiency of the Operation of the Cogeneration Steam Turbine Plants at the Variable Heat and Electric Load Schedules

Efficiency of the Operation of the Cogeneration Steam Turbine Plants at the Variable Heat and Electric Load Schedules

The Effect of Condensing Steam Turbine Exhaust Hood Body Geometry on Exhaust Performance Efficiency

The article presents data from combined numerical and experimental investigations of the effect that the overall dimensions of the exhaust hood of a steam turbine with an underslung condenser has on the aerodynamic losses in the hood. Owing to the properly selected minimum permissible overall dimensions of the exhaust hood, more efficient operation of this turbine component is achieved, better vibration stability of the turbine set shaft line is obtained, and lower costs are required for arranging the steam turbine plant in the turbine building. Experiments have shown that the main overall dimensions of the hood body have a determining effect on the exhaust hood flow path profile and on its aerodynamic performance. Owing to properly selected ratios between the exhaust hood body main sizes without a diffuser, a total loss coefficient equal to approximately unity has been obtained. By using an axial–radial diffuser, the energy loss can be decreased by 30–40% depending on the geometrical parameters and level of velocities in the inlet section of a hood having the optimal overall dimensions. By using the obtained results, it becomes possible to evaluate the overall dimensions necessary for achieving the maximal aerodynamic hood efficiency and, as a consequence, to obtain better technical and economic indicators of the turbine plant as a whole already at the initial stage of its designing. If a need arises to select overall dimensions smaller than their optimal values, the increase of energy loss can be estimated using the presented dependences. The cycle of investigations was carried out on the experimental setups available in the fundamental research laboratory of the Moscow Power Engineering Institute National University’s Department of Steam and Gas Turbines with due regard to the operating parameters and similarity criteria.

Повышение эффективности работы паротурбинных установок энергоблоков ТЭС

Повышение эффективности работы паротурбинных установок энергоблоков ТЭС

Influence of inter nal relative efficiency of steam turbine compartments on the performance of steam turbine cogeneration plant

The paper considers a steam turbine cogeneration plant that includes a back-pressure steam turbine and a natural gas-fired steam boiler that enables exhaust gas heat recovery, which is rather promising for the isolated heat and electricity consumers. A design and verification mathematical model of the steam turbine plant was developed. The focus is made on the optimization studies into the effect of the relative efficiency of turbine compartments on the performance indices of the steam turbine cogeneration plant with an installed electric capacity of 50 MW that uses the heat of steam contained in the combustion products of the boiler for heating the feed-water of the heat network.