Risk of thermal pollution of the danube passing through Serbia due to thermal power plants

A thermal power plant (TPP) uses large amounts of fresh water, mostly for cooling purposes. Among different types of cooling systems, once-through cooling is the most water-intensive and has the greatest environmental impacts. From the view-point of the steam cycle efficiency, this type of cooling still provides the most efficient electricity production, and therefore is widely used. Water is withdrawn from nearby water bodies, absorbs heat from the steam in a condenser, and then discharged back to its original source at higher temperatures causing severe environmental impacts, including fish killing, disturbing ecosystems, and heating-up natural water bodies. The total installed capacity of almost 1100 MW on the right bank of the Danube in Serbia threatens the ecosystem of this large international river due to thermal pollution. This problem will be even more pronounced in the near future, due to an inevitable increase in production capacity for new 350 MW, currently under construction. Herein, analysis of the legal framework for the protection of water from thermal pollution as well as analysis of the actual situation on the site of the TPP "Kostolac" in Serbia are presented. Based on meteorological and hydrological parameters, configuration and operation parameters of the plant, the numerical simulation of the condenser was carried on. The temperature of the water leaving condenser and amount of heat discharged back to the river are obtained. According to those results, the analysis of the existing thermal pollution of the Danube River in the flow through Serbia is given by numerical simulation using software ANSYS CFX. Analysis of thermal discharge into the Danube for the five-year period has been carried out. The cooling water effluent causes a temperature increase in the area of the right bank of the Danube, and this thermal disturbance extends along the right river bank for kilometers. Note that the flow rate of the Danube is currently large enough to compensate this thermal disturbance, but for a smaller river and/or larger electricity production capacities, this influence would have even more significant consequences on the ecosystem, making those results even more useful for further analysis

Diagnostics of maintenance technical indicators of the thermal power plants

Pouzdanost je osnovni tehnički pokazatelj koji utiče na konkurentnost termoelektrana u uslovima deregulisanog tržišta električnom energijom. Da bi se moglo upravljati ovim parametrom tokom eksploatacije, neophodno je odrediti fizičke uzroke promene pouzdanosti tokom radnog veka. U radu je analizirana eksploataciona istorija kondenzacione termoelektrane koja sagoreva mrki ugalj u prahu, na način pogodan za proračun pouzdanosti postrojenja, definisana je pouzdanost tokom eksploatacije i razmotreni su fizički uzroci njene promene tokom radnog veka.Reliability is the basic technical indicator which affects on competitiveness of thermal power plants in the terms of deregulated electricity market. Physical causes of reliability changes are important for evaluation because of it's influence on reliable management during service life. Service history of condensation type thermal power plant with coal powder combustion was analyzed in this article in the manner convenient for reliability calculations. These calculations were made in the first approximation with taking into account the physical causes of reliability exchanges

Dijagnostika tehničkih pokazatelja održavanja termoelektrane, deo II - određivanje pouzdanosti postrojenja u prvom približenju

Pouzdanost i raspoloživost su osnovni tehnički pokazatelji kvaliteta eksploatacije u najširem smislu, a time i konkurentnosti termoenergetskog postrojenja u uslovima deregulisanog tržišta električnom energijom. Eksploataciona istorija kondenzacione termoelektrane koja sagoreva ugalj u prahu, na način pogodan za proračun pouzdanosti postrojenja je analizirana u ovom radu. Proračun pouzdanosti je izveden u prvom približenju, bez analize fizičkih uzroka promene pouzdanosti tokom radnog veka.Reliability and availability are the basic technical indicators of service quality in the broadest sense, and therefore the concurrency of thermal power plants in the terms of deregulated electricity market. Service history of the condensation type thermal power plant with coal powder combustion was analyzed in this article in the manner convenient for reliability calculations. Reliability calculations was made in first approximation without analyzing physical causation of reliability exchanges

The reliability optimizing of the paper machine system by using of method of technical diagnostic

The continuous production conditions providing is the main task of the maintenance department within large industrial production systems. Today, maintenance is not viewed as an accidental activity of repairing the current damage due to the failure of parts or elements of the production system, but as a planning analysis and assessment of the situation in the sense of undertaking all necessary activities that can prevent the failures. This, very demanding role can be provided with a good selection of appropriate maintenance concepts. It is shown that for continuous production systems, the concept of condition based maintenance is very acceptable, because the analysis of the current state and the history of monitoring the behavior of system elements can timely point to a possible problem in the near future. By using the method of technical diagnostics, it is possible to increase the reliability level to a significantly higher level, thus preventing the failure of the production system and large production costs

Efficiency of operation of 300 MW condensing thermal power blocks with supercritical steam parameters in sliding pressure mode

The previous research of the application of sliding pressure has shown certain advantages in the operation of high-power condensing blocks with supercritical steam parameters in sliding pressure mode in comparison to the one with constant pressure. The maintenance of stable temperature regime and thermal expansion of turbine elements, prolongation of service life of materials of steam pipes and heating surfaces of the boiler due to the decrease in pressure of the working medium are only some of those advantages. On the other hand, the operation mode of a condensing block with sliding pressure is characterized by the change in cost-effectiveness. The result of this change is mainly due to the de-crease of steam throttling in the turbine's balancing valves and the increase of its internal action in a high pressure turbine, then also due to reduced steam consumption of the feed turbo pump just like a drop in the feed water pressure at the steam boiler inlet. A model has been developed within the framework of this study that follows such changes and their graphical interpretation is provided. The analysis results show that switching 300 MW blocks from the constant to the sliding pressure regime in the 30-60% load range increases the block efficiency respectively by 6.70-1.05%

Determination of Differential Equations of Motion and Parameters of an Elastic Internal Combustion Engine Crankshaft

The goal of this paper is to develop mathematically less complex differential equations of motion of an elastic crankshaft and their solutions with acceptable accuracy in relation to the actual system. The instantaneous angular speed of the free end of the crankshaft consists of the nonuniform rigid body motion mode and elastic deformation mode. In general, the crankshaft, as well as other parts of the engine, could be considered as a structural component with distributed mass and elasticity. This will lead to a system with an infinite number of degrees of freedom, and require solving partial differential equations. Another approach is to discretize the continuous system into a finite set of rigid bodies interconnected with springs and dampers, which is the method chosen here. The lumped mass model of the crankshaft and the corresponding differential equations of motion for each mass simulate the actual dynamics of the crankshaft fairly accurately

The influence of thermodynamic state of mineral hydraulic oil on flow rate through radial clearance at zero overlap inside the hydraulic components

In control hydraulic components (servo valves, LS regulators, etc.) there is a need for precise mathematical description of fluid flow through radial clearances between the control piston and body of component at zero overlap, small valve opening and small lengths of overlap. Such a mathematical description would allow for a better dynamic analysis and stability analysis of hydraulic systems. The existing formulas in the literature do not take into account the change of the physical properties of the fluid with a change of thermodynamic state of the fluid to determine the flow rate through radial clearances in hydraulic components at zero overlap, a small opening, and a small overlap lengths, which leads to the formation of insufficiently precise mathematical models. In this paper model description of fluid flow through radial clearances at zero overlap is developed, taking into account the changes of physical properties of hydraulic fluid as a function of pressure and temperature. In addition, the experimental verification of the mathematical model is performed

Risk of thermal pollution of the Danube passing through Serbia due to thermal power plants

A thermal power plant (TPP) uses large amounts of fresh water, mostly for cooling purposes. Among different types of cooling systems, once-through cooling is the most water-intensive and has the greatest environmental impacts. From the view-point of the steam cycle efficiency, this type of cooling still provides the most efficient electricity production, and therefore is widely used. Water is withdrawn from nearby water bodies, absorbs heat from the steam in a condenser, and then discharged back to its original source at higher temperatures causing severe environmental impacts, including fish killing, disturbing ecosystems, and heating-up natural water bodies. The total installed capacity of almost 1100 MW on the right bank of the Danube in Serbia threatens the ecosystem of this large international river due to thermal pollution. This problem will be even more pronounced in the near future, due to an inevitable increase in production capacity for new 350 MW, currently under construction. Herein, analysis of the legal framework for the protection of water from thermal pollution as well as analysis of the actual situation on the site of the TPP “Kostolac” in Serbia are presented. Based on meteorological and hydrological parameters, configuration and operation parameters of the plant, the numerical simulation of the condenser was carried on. The temperature of the water leaving condenser and amount of heat discharged back to the river are obtained. According to those results, the analysis of the existing thermal pollution of the Danube River in the flow through Serbia is given by numerical simulation using software ANSYS CFX. Analysis of thermal discharge into the Danube for the five-year period has been carried out. The cooling water effluent causes a temperature increase in the area of the right bank of the Danube, and this thermal disturbance extends along the right river bank for kilometers. Note that the flow rate of the Danube is currently large enough to compensate this thermal disturbance, but for a smaller river and/or larger electricity production capacities, this influence would have even more significant consequences on the ecosystem, making those results even more useful for further analysis