Turbine Condenser Research Articles

Methodology for studying the quality of steam condensate and cooling water of a steam turbine condenser

Monitoring the suction of cooling water into steam with measurements of , H and pH of condensate is simultaneously a characteristic of the water-chemical regime of the main loop and the system of circulating (or direct-flow) cooling and has attracted increased attention in recent years. This is due both to the signif-icant suction of cooling water into the condensing steam at the power units of TPPs and NPPs, and to the appearance on the market of new reagents – deposit and corrosion inhibitors. Investigation of the behavior of such substances under conditions of a recirculating cooling system is a complex task, the solution of which depends on many factors. The purpose of the scientific research was to develop a methodology for instrumental (automated) control based on measurements of electrical conductivity ( and H) and pH, which makes it possible to reduce the number of controlled parameters of circulating water, to increase the information content of the measurement results in terms of the amount of suction of circulating water into condensing steam.The implementation of the task in laboratory conditions was carried out using the experi-mental stand «Installation of reverse osmosis and chemical desalination», which provides the ability to measure the specific electrical conductivity of direct () and H-cationized (H) samples of steam condensate and calculate a number of normalized parameters according to the author's algorithm. A large volume of chemical quality control of the make-up and circulating water in the recirculating cooling system limits the efficiency of research and requires large labor costs. In this case, the method of indirect (calculated) deter-mination of the concentrations of ionic impurities can be used by calculating them according to the author's algorithm using the measured values of electrical conductivity and pH.Two laboratory units are presented: reverse osmosis and chemical desalination; modeling the water regime of recirculating cooling systems. A method is proposed for studying the state of the water-chemical regime of a steam turbine condenser both from the side of steam and from the side of cooling water. Examples of using the methodology for calculating the characteristics of steam condensate and cooling water are given. It is shown that the use of instrumental measurements of specific electrical conductivity and pH makes it possible to reduce the volume of laboratory chemical control of aqueous media, to increase the efficiency and information content of the measurement results.A patent for an invention of the Russian Federation No. 2658020 was obtained for a laboratory installation of reverse osmosis and chemical desalination. A distinctive feature of the installation is the ability to obtain deeply demineralized water with a specific electrical conductivity of less than 0,2 μS / cm with the subsequent preparation of extremely dilute solutions. The second laboratory unit simulates the water regime of recirculating cooling systems and can be used in the operating conditions of the power plant. The scientific novelty of the method for the chemical quality control of steam condensate and circulating water consists in the use of an original author's algorithm, which provides the calculation of a number of standardized indicators based on the measured values of electrical conductivity and pH.

Using full-flow cogeneration turbine condensate to heat various heat transfer agents

The article gives an overview of the possibilities to upgrade power plant cogeneration turbines efficiency by using low grade heat transfer agents to heat water in cogeneration systems and to increase electricity production in the heat-end mode operations. It brings up technologies based on using turbine full-flow condensate to heat initial water found in additional heaters implemented in the cogeneration turbine recovery system. Introduction of these technologies leads to an increase in steam consumption and to a decrease in enthalpy of regenerative turbine stage steam to heat the condensate, which consequently increases combined heat and power electricity production. An experimental research of cogeneration turbine recovery systems is carried out to find out the minimum and maximum initial water flow through the surface heaters implemented in the turbine recovery system and graphs are built to show the correlation between the initial heated water flow and full-flow turbine condensate temperature.

Mathematical modelling of operation modes of water intake structures’ cooling reservoirs

The article provides an overview of the tasks of studying heat and mass transfer in reservoirs with hydraulic flows of circulating water from turbine condensers. The conditions of effective reduction of the temperature of the water from the reservoir via a slotted water intake working on the principle of a hydraulic siphon are considered. The scheme of the slotted siphon-type water intake is presented, as well as its technical implementation. The system of differential equations for the numerical calculation of the parameters of cooling circulating water in reservoirs with siphon culverts is designed. An assessment of the effectiveness of the use of hydraulic slit water intakes in the cooling systems of the recycled water of thermal power plants is contained in the conclusion.

Physicochemical Analysis of Organic Impurities in the Coolant of Combined Heat and Power Plants Equipped with Combined-Cycle Power Installations

In 2018, combined-cycle power installations equipped with heat-recovery steam generators were commissioned at the combined heat and power plant nos. 1, 2, and 3 (CHPP-1, CHPP-2, and CHPP-3) in the city of Kazan. The content of organic substances in the blowdown water of clarifiers, in chemically demineralized water, in evaporating plant condensate, in heat-recovery steam generator feed water and blowdown water, and in turbine condensate was investigated. Organic substances in dry form were separated from water samples using the extraction method. The physicochemical properties and structures of the separated organic impurities were determined using an elemental analysis, infrared spectroscopy, high-efficient liquid chromatography, chromatography-mass spectrometry, and nuclear magnetic resonance methods. It was found that the content of total organic carbon (TOC) was higher than its standardized value in the heat-recovery steam generator feed water, slightly higher than the standardized value in the condensate of evaporators, and in compliance with the existing standard requirements in the turbine condensate and chemically demineralized water. Humic substances that are not removed from water during its pretreatment and enter in the heat-recovery steam generator feed water were identified as the main organic component. It is shown that ion exchange is an efficient technology for removing organic impurities from makeup water for the heat-recovery steam generator.

Study of the Rostov nuclear power plant efficiency operation under increased vacuum value

In this study, the influence of the cooling water temperature on the thermal efficiency of a conceptual pressurized-water reactor nuclear- power plant is studied. The change in the cooling water temperature can be experienced due to the seasonal changes in climatic conditions at plant site. The article presents the results of technical and economic parameters study of nuclear power unit’s operation under increased vacuum value. Investigated seasonal variations of cooling water temperature, cooling water temperature influence on the vacuum temperature in the turbine condenser, and changing the basic technical and economic performance of nuclear power station. The mathematical model of calculation the nuclear power plant operation for a 1000 MW power unit was developed.

SALTS CONCENTRATION AND DEPOSITION IN POWER PLANT COOLING SYSTEMS

The operation of circulated cooling systems (CCS), the conditions of solid deposits formation and their influence on the head transfer coefficient of heat exchangers are analyzed. Attention is drawn to the danger of jelly-like (mainly organic) deposits with thermal conductivity factor of less than 1 W/(m∙K). Deposits of such kind with the thickness of (1.0-1.5)mm reduce thermal conductivity of the walls of piping systems more than ten-fold though outside they seem to look quite secure. Deposits begin their formation mainly as calcium carbonate where microorganisms are fixed at. The example of turbine condensers shows how deposits reduce the efficiency of steam turbine units. Intensity of deposits formation and their growth are determined by the quality of cooling water and water mode of circulated cooling systems operation. Nowadays, while developing suggestions for deposits minimization, stationary mode of CCS operation is considered. However, the mode of CCS operation is changeable in time due to scarce water resources. The mode of CCS operation with variable water volume is considered in the work. It is shown that at V= var – CCS filling two variants of dependence of salts concentration on time are possible – their increase and decrease. In general, the operating mode of CCS (with respect to water flows) is described by three different dimensionless parameters that are interconnected. Regulatory documentation (SBC B.2.5-74:2013), on the requirements to quality of cooling water and water exchange mode uses models based on assumptions about stationarity of the process and the constant CCS water volume which is not always true. Therefore, the predictive reliability of such documentation is questionable.

Technology for Enhancing the Environmental Safety of Technical Water Supply to a Thermal Power Plant

The results of the study of the water-chemical and microbiological regime of operation of the cooling water recycling systems of TPP-25 and TPP-26 are presented. According to the results of the microbiological analysis of the additional and circulating water, the sources of microorganisms entering into its composition are classified and identified, the previously unknown function of the technology for deep water softening in an alkaline medium is established, which is proposed to be used to remove sediment-forming components from additional water. It is shown that for the fight against microorganisms immobilized on the inner surfaces of pipelines transporting circulating water and in turbine condensers, a biocidal treatment of circulating water is required. The results of the entire range of studies form the basis of the technology that allows to prevent precipitation of any nature on the heat transfer surfaces of turbine condensers.

The influence of air inflow in the vacuum system of a cogeneration steam turbine plant on its energy performance

The article considers the issue of the influence of air inflow in the vacuum system of a cogeneration steam turbine plant on its energy performance. The authors give a brief description of characteristics of a steam turbine condenser. On the example of the T-110/120 turbine plant, they estimate the power loss factor of a low pressure section (LPS) depending on air inflow in a vacuum system on a heat schedule operating mode with steam consumption of 20 t/h. The authors underline a significant influence of air inflow on the amount of power produced by the turbine plant. Moreover, the authors evaluate the power loss of LPS depending on air inflow in the vacuum system on one of the operation modes on the electrical schedule. They demonstrate that an increase in air inflow leads to quite large (hundreds of kilowatts) power losses.

The influence of supercooling of the main condensate at the outlet of the condenser on the operation of a cogeneration steam turbine plant

The article considers the issue of the influence of supercooling of the main condensate on the performance of a steam power plant. We describe the calculation method for a steam turbine condenser. Based on the mathematical model of a condenser, we propose a method for calculating supercooling degree of the condensate on its bottom with different air inflows in a turbo unit vacuum system. The degree of the condensate supercooling on the condenser bottom during the operation of the turbine unit in the heat and electricity production mode is determined in the example of the T-110/120-130 UTZ turbine unit. It is shown that an increase of air inflow into the vacuum system by four times leads to an increase in supercooling of the condensate from 3.5 to 11°C. It has been established that an increase in the condensate supercooling leads to additional heat losses of up to 1.100 kW in the turbine unit per a cycle in the power production operating mode and up to 500 kW per a cycle in the heat production mode.

Water Chemistry Development for a Thermal Power Plant Circulating Cooling System Using the VTIAMIN EKO-1 Chemical Agent

Numerous substances and complex chemical agents, as well as various biocides for inhibiting the growth of microbial colonies and algae, are commercially available in the market of water treatment chemicals. In frequent cases, the chemicals offered in the market are not adapted to the water chemistry conditions of power plant circulating cooling systems (CCSs), and attempts of using them may lead to violation of the circulating water or effluent (blowdown) water quality standards. The aims of this study were to investigate the effectiveness of the VTIAMIN EKO-1 chemical agent and to select its optimal dose to reduce the corrosion rate of heat transfer surfaces and prevent mineral deposits from forming on them under the conditions of the experimental bench facility simulating the operation of CCSs for the condensers of steam turbines used at combined heat and power plants (CHPPs) equipped with a PGU-450 combined-cycle power unit. During the bench tests, the circulating and makeup water quality in terms of main indicators was monitored on a daily basis. For evaluating the corrosiveness of circulating water flowing in the experimental bench facility, a pair of corrosion rate surveillance specimens (coupons) made of St. 20 carbon steel and one brass coupon were installed at all test stages. The circulating water scale-forming properties were evaluated based on the results from visual examination and weighing of the thermal electric heater and the surveillance specimen made of stainless steel as well as the stabilization coefficient (calcium transport) calculation results. After having been evaporated, the CHPP makeup water that has not been subjected to corrective (reactant) treatment has increased scale-forming and corrosive properties with respect to carbon steels and medium-level scale-forming and corrosive properties with respect to brass. By using the VTAMIN EKO-1 chemical agent in the optimal dose, the carbon steel corrosion rate was slowed down by a factor of 3.7; the linear deposit-formation rate was decreased by a factor of 27.5, and the stabilization coefficient was kept at a level of 95.72%. In so doing, the requirements posed to the chemical agent’s key components by the standards for fishery water bodies were not violated. With the average content of the VTIAMIN EKO-1 reagent in circulating water at a level of 9.54 mg/dm3, its effectiveness in terms of corrosion protection and prevention of scale formation has been demonstrated. The estimated demand for the chemical agent is 33 397 kg/year.

Optimization Investigations of a Combined Binary-Cycle Geothermal Power Plant with Two Separation Pressures and Flashed Steam Superheating Using a Hydrogen–Oxygen Steam Generator

The article considers the specific features of and prospects for improving the efficiency of geothermal power plants (GeoPPs) that use a steam–water mixture from geothermal fields and steam superheating as an energy source. The process flow diagram of a combined binary-cycle GeoPP with two separation pressures and flashed steam superheating with the use of a hydrogen–oxygen steam generator is proposed. The advisability of using a separator downstream of the high-pressure section for decreasing the steam moisture at the turbine condenser inlet is substantiated. The article also presents the results from numerical optimization investigations of the effect that the choice of organic working fluid has on the efficiency, safety, and environmental characteristics of the binary installation used as part of a combined-cycle GeoPP. The following groups of organic substances as possible candidates for use as working fluid are considered: nontoxic, nonflammable, and nonexplosive ones (group I); low-toxic, nonflammable, and nonexplosive ones (group II); nontoxic inflammable ones (group III); and low-toxic, inflammable, and explosive ones (group IV). Typical dependences characterizing the effect that the pressure in the expander and the saturation pressure in the evaporator have on the binary turbine net power output, on the specific flowrate of separated geothermal brine per unit power capacity, on the binary cycle efficiency, and on the GeoPP efficiency as a whole are shown taking as examples the use of cyclobutane and octafluoropropane as a working fluid. For a few working fluids, the existence of extremes in the above-mentioned dependences is established, which determine the binary installation optimal power values and the minimal geothermal brine specific flowrate. Based on the numerical analysis results, limitations are imposed on the admissible maximum and minimum pressure values in the binary circuit. Bar charts of calculated process characteristics influencing the binary turbine flow path’s design and efficiency are plotted. A priority (according to the maximum net power output criterion) list of working fluids relating to the group of environmentally friendly organic substances for the combined-cycle GeoPP binary installation with flashed steam superheating taking into account process-related limitations is drawn up.

EXERGY ANALYSIS ON THERMAL POWER PLANT PT. MAKASSAR TENE USING CYCLE-TEMPO 5

Analyzing exergy on the power plant generating system specially at PLTU, efficient utilization of energy resources can be obtained particularly since it leads efforts to reduce energy waste that already exists.The purposes of this research are to get the Thermal Power Plant system modeling of PT. Makassar Tene, to get the value of modeled exergy power plant system, to get exergy losses, to get the amount exergy efficiency and to get the cost of exergy losses.The research method was firstly, designing the Power Plant generating systems PT. Makassar Tene using Cycle-Tempo 5 as thermodynamic analysis tool. Results of calculations were then used to calculate the exergy profile.Exergy values analyzed on a system modeled Power Plant consists of turbine components, condensers and pump. Boilers are not included in the analysis because of the input device is not contained and the mass flow rate of the boiler occurs steady state in which the state of the same process with the state of the environment so that there is no exergy difference that can be utilized.The highest exergy losses based on the modelling was on the turbine components that was 10201.50 kW. This was due to the change in the vapor phase into the liquid phase contained in the component before and after leaving the turbine components. While the lowest exergy losses was on the pump component, that was 437.18 kW.The higher the efficiency value of a component, the better its performance is. The highest efficiency value of exergy that was 51.43% contained on the turbine components. While the lowest efficiency value of exergy was 0%.

Mathematical calculation of additional cooling methods to achieve the established temperature regime at the reservoir-cooler of Zainskaya state district power plant

A natural and technical complex, including the industrial part - the turbine condenser and cooling system, and the natural part - the cooling reservoir with the surrounding atmosphere, is one of the options for the operation of the circulating system technical water supply of thermal power station and nuclear power station. For cooling equipment Zainskaya state district power plant as a pond-cooler is used Zainskoe reservoir. According to the available data on the reservoir-cooler of Zainskaya state district power plant, the average water temperature in comparison with the natural temperature of the water body in summer months exceeds the current requirements, which negatively affects the functioning of the reservoir and the operation of the power plant itself. The mathematical analysis of the reservoir cooling capacity and the technical justification for the introduction of additional methods for achieving the optimum temperature regime at the point of heat exchange water discharge of the Zainskaya state district power plant are carried out in the article. According to the obtained results, the expected water temperature in the hottest month of the year as a result of wastewater discharge will not exceed a critical temperature maximum of 28 ° C.

Thermodynamic and Exergoeconomic Analyses of a Novel Combined Cycle Comprised of Vapor-Compression Refrigeration and Organic Rankine Cycles

In this study, a cooling/power cogeneration cycle consisting of vapor-compression refrigeration and organic Rankine cycles is proposed and investigated. Utilizing geothermal water as a low-temperature heat source, various operating fluids, including R134a, R22, and R143a, are considered for the system to study their effects on cycle performance. The proposed cycle is modeled and evaluated from thermodynamic and thermoeconomic viewpoints by the Engineering Equation Solver (EES) software. Thermodynamic properties as well as exergy cost rates for each stream are found separately. Using R143a as the working fluid, thermal and exergy efficiencies of 27.2% and 57.9%, respectively, are obtained for the cycle. Additionally, the total product unit cost is found to be 60.7 $/GJ. A parametric study is carried out to determine the effects of several parameters, such as turbine inlet pressure, condenser temperature and pressure, boiler inlet air temperature, and pinch-point temperature difference, on the cycle performance. The latter is characterized by such parameters as thermal and exergy efficiencies, refrigeration capacity, produced net power rate, exergy destruction rate, and the production unit cost rates. The results indicate that the system using R134a exhibits the lowest thermal and exergy efficiencies among other working fluids, while the systems using R22 and R143a exhibit the highest energy and exergy efficiencies, respectively. The boiler and turbine contribute the most to the total exergy destruction rate.

Studying the mutual interaction of hydraulic characteristics of water­distributing pipelines and their spraying devices in the coolers at energy units

This analytical study is based on the results from hydraulic tests of spray nozzles for the mixing (waterjet) steam condenser at a thermal power plant's turbo generator. The work was performed at the stage of launch operations at TPP. Such hydraulic tests were carried out by co-authors at the stage of launch operations at Razdan TPP (Armenia). The TPP is located in a mountainous region with a limited water supply; the plant's features include: dry cooling of circulating water in the radiator cooling towers; a steam condenser of mixing type.The main tasks of hydraulic tests were: to determine the actual throughput capacity, to find a flow rate coefficient for the nozzles of a steam condenser, as well as analyze their operation in a vacuum in the condenser.This study considered the nozzles that have two openings with a diameter of 13 mm and 15 mm for spraying cooling water within the steam space of the condenser.By exploring the hydraulic characteristics Q=f(H) of standard nozzles mounted at the end of a water-distributing pipeline, it was found that the diameter of the nozzle opening did not significantly affect the flow rate of water under the same water heads. Such a result is explained by that the pipeline's characteristic was obtained, rather than that of the spraying device.The further hydraulic study into the nozzles was performed at a special laboratory bench.The established factor of interrelation between the hydraulic characteristics of a water-distributing pipeline and the nozzles mounted onto it is important for performing similar studies.The throughput capacity of the nozzles, considering the presence of a vacuum in the steam condenser of a turbo generator will be larger than that under atmospheric conditions. However, in a closed system of water circulation, the overall water flow rate of nozzles will equal the supply of cooling water from pumps into a given system. Therefore, the supply of cooling water to a condenser will not change dramatically, while the water flow rate of a single nozzle will be inversely proportional to their number.In addition, we investigated a possibility to increase the feed of water to a condenser in order to improve energy performance. Our analysis reveals the impossibility of a substantial increase in the water supply to a condenser by increasing the diameters of spraying nozzles' openings. This does not substantially reduce the overall loss of water head and feed from circulating pumps to the steam cooling system in a turbine's condenser.

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.

Entransy based optimal adjustment of louvers for anti-freezing of natural draft dry cooling system

Natural draft dry cooling tower (NDDCT) is susceptibly affected by ambient conditions, especially environmental temperature and natural wind. The performance should be improved during winter but faces a freezing risk. The traditional modifications to relieve the adverse influence of winter chills were mainly based on “try and error”. In this study, concentrating on the potential of airside adjustments of louvers, a 3D numerical model of large-scale dry cooling system of the whole coal-fired power plant is established. The inherent mathematical relationships of heat transfer processes in each column of NDDCT and condenser of turbine are deduced in the view of entransy. A global optimal control of opening degrees of louvers of NDDCT under crosswinds during winter is proposed. Taking a practical 660 MW supercritical dry cooling power generating unit located in north China as object, the potential of releasing the freezing risk by airside adjustment of louvers is revealed under both natural wind and winter chill conditions.

The Fault Diagnostics Methods for the Operation Process in a Steam Turbine Condenser

The Fault Diagnostics Methods for the Operation Process in a Steam Turbine Condenser

Efficiency of Using Built-In Bundles of Cogeneration Steam Turbine Condensers for Make-up Water Heating

Efficiency of Using Built-In Bundles of Cogeneration Steam Turbine Condensers for Make-up Water Heating

Methods of Heat-Exchange Intensification in NPP Equipment

The aims and problems of research on the means for intensifying heat exchange in the equipment of nuclear power plants are examined: nuclear reactors, steam generators, turbine condensers, heat-exchangers of dry water cooling towers, intermediate separators-steam superheaters of turbines, heat-exchange apparatus of safety systems, turbo-electro-generators, oil coolers, feed-water heaters. Methods of identifying heat-exchange are analyzed: different types of finning, turbulence generators and swirlers of one- and two-phase flows, coating on heating surfaces, systems with mixed flow. Computational recommendations are made for determining the intensity of heat emission from promising types of heat-exchange surfaces: bundles of lowfinned tubes and spiral coils.