Analysis of the evaporative towers cooling system of a coal-fired power plant

The paper presents the results of measurements and calculations concerning the influence of weather conditions on the operation of wet cooling towers of 905 MWe units of the Opole Power Plant (Poland). The research concerned the influence of temperature and relative humidity of air, wind and power unit load on the water temperature at the outlet from the cooling tower, the level of water cooling, cooling efficiency and cooling water losses. In the cooling water loss, the evaporation loss stream and the drift loss stream were distinguished. In the analyzed operating conditions of the power unit, for example, an increase in Tamb air by 5 °C (from 20–22˚C to 25-27˚C) causes an increase in temperature at the outlet of the cooling tower by 3-4˚C. The influence of air temperature and humidity on the level of water cooling ΔTw and cooling efficiency ε were also found. In the case of ΔTw, the effect is in the order of 0.1-0.2˚C and results from the change in cooling water temperature and the heat exchange in the condenser. The ε value is influenced by air temperature and humidity, which determine the wet bulb temperature value. Within the range of power changes of the unit from 400 to 900 MWe, the evaporated water stream mev, depending on the environmental conditions, increases from 400-600 tons/h to the value of 1000-1400 tons/h. It was determined that in the case of the average power of the unit at the level of 576.6 MWe, the average values of the evaporation and drift streams were respectively 0.78% and 0.15% of the cooling water stream. Using statistical methods, it was found that the influence of wind on the level of water cooling, cooling efficiency and cooling water losses was statistically significant.

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“…This increase is strongly dependent on the ambient temperature T amb . These results are consistent with the results presented in [32].…”

Section: Resultssupporting

confidence: 94%

Impact of Weather Conditions on the Operation of Power Unit Cooling Towers 905 MWe

et al. 2021

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“…For the calculation of heat exchange in cooling towers it is assumed that the coefficients amounts a ¼ 0.119, b¼ À 1.575, and c ¼ 40. 10 With such constants adopted, on the field of water temperature for referent plant, thus calculate the enthalpy of saturated air shows very little deviation from the values obtained from the diagrams.…”

Section: Thermodynamic and Mathematical Model Of Reference Plantmentioning

confidence: 94%

“…Cooling water temperature leaving cooling tower system was also measured in those intervals, and mean values of every measured data was used in the power plant cold-end simulation. 10 For the present state, with specific mass flow rate of 3.846 kg/m 2 s, the results of the measurements for one summer day are given in Figure 3.…”

Section: Thermodynamic and Mathematical Model Of Reference Plantmentioning

confidence: 99%

“…The variation of ambient air parameters can be great during a day or month; they will cause the variation of cooling tower heat capacity and supply water temperature. 10 Many factors determine the type, size, and shape of a cooling tower. The final choice is determined by many factors such as individual user requirements, economic considerations, local weather patterns, and esthetics.…”

Section: Introductionmentioning

confidence: 99%

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Improving the energy efficiency of a 110 MW thermal power plant by low-cost modification of the cooling system

Jović

Laković

Banjac

2018

Energy & Environment

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The electric power system of the Republic of Serbia relies mostly on lignite-fired thermal power plants, with 70% of the total electricity generation. Most of these plants are over 30 years old, and investment in their modernization is necessary. The energy efficiency of the 110 MW coal-fired power plant in which the condenser is cooled by the mechanical draught wet cooling towers system is analyzed in this paper. Attention is primarily devoted to operating conditions of the cold end of the plant, i.e. to the interrelationship of the condenser and cooling towers. Most important parameters that affect the operation of the cooling towers system are ambient air temperature and relative humidity, specific mass flow rate, and temperature of cooled water. With the existing cooling system, the overall energy efficiency of the plant is low, especially in the summer months, even less than 30%, due to adverse weather conditions. By upgrading existing cooling tower system by adaptation of two additional cooling tower cells, overall energy efficiency can be increased by 1.5%. The cooling tower system rehabilitation investments payback period is estimated to be less than one year. Static method for economic and financial assessment is used.

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“…Definition of thermal pollution is precisely the change in temperature of natural waters (rivers, lakes, oceans) due to human activity [4,5]. It should be kept in mind that the energy efficiency of power plants with oncethrough cooling is higher up to 5% compared to plants with a closed-cycle cooling, due to lower temperature of the cooling water [6]. Therefore, wherever possible, large thermal power capacities are being built on the banks of large rivers, in order to simultaneously provide the required amount of cooling water and obtain better energy efficiency of plants producing electricity.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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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 viewpoint 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.

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Analysis of the evaporative towers cooling system of a coal-fired power plant

Cited by 6 publications

References 7 publications

Impact of Weather Conditions on the Operation of Power Unit Cooling Towers 905 MWe

Impact of Weather Conditions on the Operation of Power Unit Cooling Towers 905 MWe

Improving the energy efficiency of a 110 MW thermal power plant by low-cost modification of the cooling system

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

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