Improvement of corrosion process control techniques at engineering facilities under high parameters of water coolants

2019 ◽  
Vol 18 (4) ◽  
pp. 414-420
Author(s):  
V. N. Shcherbakov
Keyword(s):  
Power Plants ◽  
Dissociation Constants ◽  
Thermal Power ◽  
Lithium Hydroxide ◽  
Operational Control ◽  
Acceptable Error ◽  
Equivalent Conductance ◽  
Conductivity Sensor ◽  
Wide Range ◽  
Molar Equivalent

Introduction. The work objective is to increase the reliability of the prediction methods for the lithium hydroxide behavior in the steam-water circuit at the thermal power plants and nuclear power plants, and for the operational monitoring of the pH index of steam solutions. A method of operational control is developed on the basis of the conductometric measurements of the hydrogen index of the corrosion inhibitor vapor solutions for construction materials of lithium hydroxide used at the TPP and NPS.Materials and Methods. A mathematical model method is used for the practical implementation of the high-temperature operational control of the steam solution pH index.Research Results. A method for monitoring the pH of vapor solutions of lithium hydroxide based on the determination of vapor concentration through the steam condensation in the coolable conductivity sensor located in the vapor space of the steam generator is developed. This has significantly improved the accuracy of determining the lithium hydroxide concentration. Equations describing the change in the limiting molar equivalent conductance and dissociation constants of lithium hydroxide in a wide range of state change parameters are proposed.Discussion and Conclusions. The proposed on-line technique of testing the pH value of steam solutions, and mathematical models for calculating the limiting molar equivalent conductance and dissociation constants provide an acceptable error level calculations and the capability of measurements automation. With an increase in the vapor temperature up to 573.15 K, the necessity arises to fortify lithium hydroxide in the vapor to 10-2 mol/kg.

scholarly journals Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1267
Author(s):  
David Längauer ◽  
Vladimír Čablík ◽  
Slavomír Hredzák ◽  
Anton Zubrik ◽  
Marek Matik ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Product Analysis ◽  
Coal Combustion Products ◽  
X Ray ◽  
Wide Range ◽  
Silica Alumina

Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

scholarly journals SYSTEM OF AUTOMATIC CONTROL OF THE LEVEL OF STEAM POWER GENERATORS ON THE BASIS OF THE REGULATION CIRCUIT WITH SMOOTHING OF THE SIGNAL

2021 ◽  
Vol 22 (1) ◽  
pp. 287-297
Author(s):  
Dilnoza Umurzakova
Keyword(s):  
Automatic Control ◽  
Water Level ◽  
Power Plants ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Steam Generators ◽  
Wide Range ◽  
Steam Boilers ◽  
The Impact

The purpose of this article is to develop high-quality combined automatic control systems (ACS) for the water level in the drum of steam boilers of thermal power plants (TPPs), which can significantly improve the quality of regulation and increase the efficiency of TPPs in a wide range of load changes. To improve the quality of water level control in the drum of steam generators of nuclear power plants with a pressurized water-cooled power reactor (PWPR), it is proposed to use a combined automatic control system based on a control loop with a correcting PI-controller tuned to a symmetrical optimum, with smoothing the reference signal and device compensation of the most dangerous internal and external measurable disturbances. A technique has been developed for assessing the impact of changes in the quality characteristics of transients of combined self-propelled guns by the water level in the drum of steam boilers and steam generators on the safety, reliability, durability, and efficiency of thermal power equipment of thermal power plants. Comparison was made of direct indicators of the quality of three ACS (typical and three-pulse, digital system with an observer state, and the proposed combined ACS). The simulation results of transients of the proposed and typical three-pulse self-propelled guns confirmed the advantages of the first. ABSTRAK: Artikel ini bertujuan bagi membina sistem kombinasi automatik (ACS) berkualiti tinggi bagi aras air dalam drum dandang stim tenaga terma logi kuasa (TPP). Ini dapat meningkatkan mutu peraturan dan meningkatkan kecekapan TPP secara signifikan dengan pelbagai perubahan beban. Bagi meningkatkan kualiti kawalan aras air dalam drum penjana wap loji kuasa tenaga nuklear dengan reaktor berpendingin air bertekanan (PWPR). Gabungan sistem kawalan automatik berdasarkan gelung kawalan dengan pembetulan PI telah dicadangkan dan diselaraskan simetri secara optimum, dengan melancarkan isyarat rujukan dan pembetulan peranti dari gangguan yang boleh diukur dari dalam dan luar. Satu teknik telah dibina bagi menilai kesan perubahan ciri kualiti transien gabungan berjentera pada aras air di tong dandang stim dan drum penjana wap pada keselamatan, kebolehpercayaan, ketahanan dan kecekapan peralatan tenaga terma loji janakuasa. Perbandingan dibuat pada kualiti tiga ACS (sistem digital khas dan tiga signal dengan keadaan pemerhati dan gabungan ACS yang dicadangkan). Hasil sistem simulasi transien yang dicadangkan dan tiga signal biasa berjentera mengesahkan kelebihan pada yang pertama.

scholarly journals THE ELECTROFILTER ASH OF GACKO THERMAL POWER PLANT AS TECHNOGENIC RAW MATERIAL AND THE IMPACT OF ASH WASTE PILEON THE ENVIRONMENT

2016 ◽  
Vol 1 (15) ◽  
Author(s):  
Ljiljana Crnogorac ◽  
Boško Vuković
Keyword(s):  
Coal Combustion ◽  
Power Plants ◽  
New Technologies ◽  
Thermal Power ◽  
Raw Material ◽  
Significant Progress ◽  
Negative Effects ◽  
Wide Range ◽  
The Impact ◽  
Made In

During the working of thermal power plants, due to technological process of coal combustion, wastematter, which takes up large areas of land, degrades and pollutes the environment, is created. In the lastyears, a significant progress has been made in the world in researching new technologies thatimplement technogenic materials which have wide range of optimal economic use.An example for thisis electrofilterash which is, as technogenic raw material,largly and more often used in building industry.This resulted in decreasing negative effects of ash which was deposited considerably on ash waste piles.The use of ash for different industry purposes decreases the costs, increases a company's profitandremoves the negative effects on the environment and human health.

scholarly journals Increasing the efficiency of the thermal power units at zoning of heat load curve

2019 ◽  
Vol 21 (4) ◽  
pp. 12-19
Author(s):  
D. S. Sinelnikov ◽  
P. A. Shchinnikov
Keyword(s):  
Fuel Consumption ◽  
Heat Load ◽  
Heat Supply ◽  
Power Plants ◽  
Thermal Power ◽  
Original Method ◽  
Load Curve ◽  
Temperature Schedule ◽  
Wide Range ◽  
Material Energy

The article deals with the work of heat and power units of thermal power plants in the conditions of disaggregation of the heat load schedule. The purpose of the work is to increase the efficiency of operation of CHP units operating under the conditions of the zoned temperature schedule. To achieve the obtained results, mathematical modeling based on the methods of differential-exergetic and thermodynamic analysis; methods of material, energy and exergetic balances. Research has shown that in order to increase the efficiency the original method of splitting the temperature graph into three zones can be used, each of which is characterized by the method of regulation of heat supply, and to assess the effect of the minimum fuel consumption criterion can be used. The method of determining the equivalent design temperature, which takes into account the regime peculiarities of heat and power units in the form of a method of regulation of heat supply, is developed. Study has shown that three design points should be available when zoning the temperature schedule. Based on optimization calculations for standard sizes of heat and power units of a wide range of capacities, the calculations show that the optimal parameters of heat and power units in the conditions of zoning of the temperature schedule as a whole correspond to the standard values. In addition, it is shown that in each zone of the temperature schedule there is a saving of fuel, which can be from 3 to 30% depending on the type of power unit, its capacity and zone of the temperature schedule, and the annual fuel consumption of the heat and power units can be reduced by approximately 10%. It is shown that when conventional power units operate according to the zoned temperature schedule and in the first zone (quantitative regulation), preference should be given to power units with steam production. In the second zone (mixed regulation), the operation of power units with steam extraction and heat and power units is equivalent. In addition, in the third zone (qualitative regulation) preference should accrue to heat and power units.

scholarly journals Comparative analysis of the Allam cycle and the cycle of compressorless combined cycle gas turbine unit

2020 ◽  
Vol 209 ◽  
pp. 03023
Author(s):  
Mikhail Sinkevich ◽  
Anatoliy Kosoy ◽  
Oleg Popel
Keyword(s):  
Comparative Analysis ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Thermal Power ◽  
District Heating ◽  
Combined Cycle ◽  
Working Fluid ◽  
District Heating System ◽  
Wide Range

Nowadays, alternative thermodynamic cycles are actively studied. They allow to remove CO2, formed as a result of fuel combustion, from a cycle without significant energy costs. Calculations have shown that such cycles may meet or exceed the most advanced power plants in terms of heat efficiency. The Allam cycle is recognized as one of the best alternative cycles for the production of electricity. Nevertheless, a cycle of compressorless combined cycle gas turbine (CCGT) unit is seemed more promising for cogeneration of electricity and heat. A comparative analysis of the thermal efficiency of these two cycles was performed. Particular attention was paid to ensuring equal conditions for comparison. The cycle of compressorless CCGT unit was as close as possible to the Allam cycle due to the choice of parameters. The processes, in which the difference remained, were analysed. Thereafter, an analysis of how close the parameters, adopted for comparison, to optimal for the compressorless CCGT unit cycle was made. This analysis showed that these two cycles are quite close only for the production of electricity. The Allam cycle has some superiority but not indisputable. However, if cogeneration of electricity and heat is considered, the thermal efficiency of the cycle of compressorless CCGT unit will be significantly higher. Since it allows to independently regulate a number of parameters, on which the electric power, the ratio of electric and thermal power, the temperature of a working fluid at the turbine inlet depend. Thus, the optimal parameters of the thermodynamic cycle can be obtained in a wide range of operating modes of the unit with different ratios of thermal and eclectic powers. Therefore, the compressorless CCGT unit can significantly surpass the best steam turbine and combined cycle gas turbine plants in district heating system in terms of thermal efficiency.

scholarly journals Transient Simulation of Geothermal Combined Heat and Power Generation for a Resilient Energetic and Economic Evaluation

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 894 ◽  
Author(s):  
Tim Eller ◽  
Florian Heberle ◽  
Dieter Brüggemann
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Combined Heat And Power ◽  
Heat Extraction ◽  
Exergetic Efficiency ◽  
District Heating System ◽  
Transient Model ◽  
Additional Heat ◽  
Wide Range

Geothermal power plants based on the organic Rankine cycle (ORC) are used to convert the thermal power of brine into electricity. The efficiency and profitability of these power plants can be increased by an additional heat supply. The purpose of this study is to evaluate different combined heat and power (CHP) concepts for geothermal applications by thermodynamic and economic considerations. Therefore, a dynamic simulation model of a double-stage ORC is developed to perform annual return simulations. The transient ORC model is validated in a wide range by operational data of an existing power plant in the German Molasse Basin. A district heating system is considered and the corresponding heat load profiles are derived from a real geothermal driven heating network. For CHP, parallel and combined configurations are considered. The validation of the transient model is satisfying with a correlation coefficient of 0.99 between the simulation and real power plant data. The results show that additional heat extraction leads to a higher exergetic efficiency and a higher profitability. The exergetic efficiency and the profitability are increased by up to 7.9% and 16.1%, respectively. The combined concept shows a slightly better performance than the parallel configuration. The efficiency can be increased by up to 1.3%. In economic terms, for CHP the annual return can be increased by at least 2,500,000 €. In principle, the dynamic model shows reliable results for high power gradients. This enables an investigation of geothermal ORC models for the reserve market in future works.

scholarly journals Plasma ignition of dust-coal flame

2019 ◽  
Vol 17 (1) ◽  
pp. 14-22
Author(s):  
V. E. Messerle ◽  
A. B. Ustimenko ◽  
K. A. Umbetkaliev
Keyword(s):  
Plasma Torch ◽  
Power Plants ◽  
Thermal Power ◽  
Fuel Mixture ◽  
Ash Content ◽  
Environmental Indicators ◽  
Pulverized Coal ◽  
Fuel Oil ◽  
Start Up ◽  
Wide Range

One of the promising power engineering technologies is the plasma thermochemical preparation of pulverized coal to burning using plasma-fuel systems (PFS). This technology allows increasing the efficiency of fuel use and environmental indicators of thermal power plants, as well as eliminating the use of fuel oil, traditionally used to start-up the boilers and stabilize the combustion of a pulverized coal flame. This paper presents the results of numerical experiments on ignition of pulverized coal in PFS. PFS is designed for fuel oil-free start-up of the boilers and stabilization of pulverized coal flame, and represents a pulverized coal burner equipped with plasma torch. Via PlasmaKinTherm software which combines kinetic and thermodynamic methods of calculating the processes of motion, heating, thermochemical transformations and fuel mixture ignition in the volume of PFS, impact of the power of the plasma torch and ash content of coal onto efficiency of fuel mixture ignition have been determined. Also one of the main regime parameters of PFS providing ignition of the fuel is concentration of coal dust in the fuel mixture which can vary within a wide range. Therefore, conditions for fuel mixture ignition in PFS have been investigated, depending on the concentration of coal in the fuel mixture in the range from 0.4 to 1.8 kg of coal per 1 kg of air. Calculations were performed for cylindrical PFS of 0.2 m diameter and 2 m of length at fixed consumption of coal (1000 kg/h) and the plasma torch power (60 kW) for three values of coal ash content (20, 40 and 70%). The basic regularities of the process of plasma thermochemical preparation of fuel for burning were revealed.

scholarly journals Quasi Natural Approach for Crystallization of Zeolites from Different Fly Ashes and Their Application as Adsorbent Media for Malachite Green Removal from Polluted Waters

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1064
Author(s):  
Denitza Zgureva ◽  
Valeria Stoyanova ◽  
Annie Shoumkova ◽  
Silviya Boycheva ◽  
Georgi Avdeev
Keyword(s):  
Chemical Composition ◽  
Malachite Green ◽  
Power Plants ◽  
Thermal Power ◽  
Alkaline Treatment ◽  
Heterogeneous Structure ◽  
Fly Ashes ◽  
X Ray ◽  
Natural Approach ◽  
Wide Range

Worldwide disposal of multi-tonnage solid waste from coal-burning thermal power plants (TPPs) creates serious environmental and economic problems, which necessitate the recovery of industrial waste in large quantities and at commercial prices. Fly ashes (FAs) and slag from seven Bulgarian TPPs have been successfully converted into valuable zeolite-like composites with various applications, including as adsorbents for capturing CO2 from gases and for removal of contaminants from water. The starting materials generated from different types of coal are characterized by a wide range of SiO2/Al2O3 ratio, heterogeneous structure and a complex chemical composition. The applied synthesis procedure resembles the formation of natural zeolites, as the raw FAs undergo long-term self-crystallization in an alkaline aqueous solution at ambient temperature. The phase and chemical composition, morphology and N2 adsorption of the final zeolite products were studied by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-Ray Diffraction (XRD) and Brunauer–Emmett–Teller (BET) analyses. The growth of faujasite (FAU) crystals as the main zeolite phase was established in all samples after 7 and 14 months of alkaline treatment. Phillipsite (PHI) crystals were also observed in several samples as an accompanying phase. The final products possess specific surface area over 400 m2/g. The relationships between the surface properties of the investigated samples and the characteristics of the raw FAs were discussed. All of the obtained zeolite-like composites were able to remove the highly toxic dye (malachite green, MG) from water solutions with efficiency over 96%. The experimental data were fitted with high correlation to the second-order kinetics.

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