scholarly journals Experimental study of the thermochemical treatment of the low-grade coal prior to boiler combustion at coal-fired power station

2019 ◽  
Vol 109 ◽  
pp. 00119
Author(s):  
Volodymyr Yemelianenko ◽  
Vitalii Pertsevyi ◽  
Oleksandr Zhevzhyk ◽  
Iryna Potapchuk ◽  
Oleksandr Lutai
Keyword(s):  
Experimental Study ◽  
Power Plants ◽  
Thermal Power ◽  
Thermochemical Treatment ◽  
Gas Pressure ◽  
Pulverized Coal ◽  
Time Range ◽  
Low Grade ◽  
Boiler Furnace ◽  
Coal Fuel

Analysis of the perspectives of the coal fuel for thermal power plants is carried out. The necessity of the experimental study for temperature measurement in the boiler furnace. The results of the experimental study are presented: temperature change over time at the burner outlet for different constant pressure value of the backlighting gas, dependence of the temperature at the burner outlet from the backlighting gas pressure for constant concentration value of pulverized coal in coal-air mixture, dependence of the temperature at the burner outlet from the concentration of pulverized coal in coal-air mixture for constant value of the backlighting gas pressure, temperature measurements for constant backlighting gas pressure value, constant value of the concentration of pulverized coal in coal-air mixture when plasmatron is switched and operates for some time range. The results of the study could be applied to the solid fuel treatment for different thermal units.

Improved method to mitigate the effect of coal fuel switching on critical process parameters of a steam generator in a thermal power plant

2011 ◽  
Vol 225 (8) ◽  
pp. 1026-1040 ◽  
Author(s):  
S Dharmalingam ◽  
L Sivakumar ◽  
T Anandhi ◽  
M Umapathy
Keyword(s):  
Process Parameters ◽  
Power Plants ◽  
Thermal Power ◽  
Improved Method ◽  
Heating Value ◽  
Fuel Switching ◽  
Coal Fuel ◽  
Embedded Controller ◽  
Critical Process Parameters ◽  
Critical Process

The design and performance of steam generators supplied to thermal power plants are greatly influenced by the properties of coal burnt. All coals are not same and the variation of heating value of coal supplied to boiler results in changes in critical process parameters like pressure and temperature of main steam produced. These fluctuations are normally controlled by master pressure controller, provided the variation in heating value is within certain limits. If the heating value of coal being burnt varies substantially, a remedial measure is necessary to control the pressure and temperature fluctuations during coal fuel switching. The composition of the coal burnt currently in a boiler is determined from an online analyser, and an embedded controller computes the current heating value of the coal and suitably modifies the gains of all the controllers to arrest the undue fluctuations in pressure and temperature. A validated mathematical model for a typical 500 MW plant is used to simulate the variations in pressure and temperature of steam with normal and embedded controllers. Significant reduction in pressure and temperature variation has been achieved with an embedded controller. This article discusses the improved method of ensuring optimum boiler performance during coal fuel switchover.

Mechanism of Upgrading Low-Grade Solar Thermal Energy and Experimental Validation

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Hui Hong ◽  
Hongguang Jin ◽  
Jun Sui ◽  
Jun Ji
Keyword(s):  
Energy Level ◽  
Thermal Energy ◽  
Power Plants ◽  
Thermal Power ◽  
Chemical Energy ◽  
Solar Thermal ◽  
Low Grade ◽  
Thermal Power Plants ◽  
Solar Thermal Energy ◽  
Middle Temperature

Solar thermochemical processes inherently included the conversion of solar thermal energy into chemical energy. In this paper, a new mechanism of upgrading the energy level of solar thermal energy at around 200°C was revealed based on the second law thermodynamics and was then experimentally proven. An expression was derived to describe the upgrading of the energy level from low-grade solar thermal energy to high-grade chemical energy. The resulting equation explicitly reveals the interrelations of energy levels between middle-temperature solar thermal energy and methanol fuel, and identifies the interactions of mean solar flux and the reactivity of methanol decomposition. The proposed mechanism was experimentally verified by using the fabricated 5kW prototype of the receiver∕reactor. The agreement between the theoretical and the experimental results proves the validity of the mechanism for upgrading the energy level of low-grade solar thermal energy by integrating clean synthetic fuel. Moreover, the application of this new middle-temperature solar∕methanol hybrid thermochemical process into a combined cycle is expected to have a net solar-to-electric efficiency of about 27.8%, which is competitive with other solar-hybrid thermal power plants using high-temperature solar thermal energy. The results obtained here indicate the possibility of utilizing solar thermal energy at around 200°C for electricity generation with high efficiency by upgrading the energy level of solar thermal energy, and provide an enhancement to solar thermal power plants with the development of this low-grade solar thermochemical technology in the near future.

scholarly journals Enhancement of Technical and Economic Indicators of Power-Generating Units of Thermal Power Plants by Eliminating Flue Gas Recirculation

2021 ◽  
Vol 7 (1) ◽  
pp. 26-31
Author(s):  
Taras Kravets ◽  
◽  
Yevhen Miroshnychenko ◽  
Andrii Kapustianskyi ◽  
◽  
...  
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Gas Flow ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Boiler Furnace ◽  
Short Run ◽  
Boiler Units ◽  
Coal Drying ◽  
Efficiency Indicators

Boiler units at Ukrainian thermal power plants need to be modernized or replaced in the short run, as this is important for the national energy security. The authors determined one of possible ways to improve the efficiency indicators of coal-fired boiler units and power generating units as a whole up to the values exceeding the design ones. This variant of improvement consists in abandoning the technology of using flue gas as drying agent in pulverized coal systems and replacing it with direct discharge of the gas flow into the boiler furnace. Numerous computations were carried out to study the change of efficiency indicators and manoeuvrability of power generating units due to the replacement of the ball mill pulverizing system using flue gases for coal drying with the scheme including ball-and-race mills that use hot air as drying agent.

scholarly journals Review of the investigations of pulverized coal combustion processes in large power plants in laboratory for thermal engineering and energy: Part B

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1611-1626
Author(s):  
Predrag Stefanovic ◽  
Dejan Cvetinovic ◽  
Zoran Markovic ◽  
Milic Eric ◽  
Simeon Oka ◽  
...  
Keyword(s):  
Coal Combustion ◽  
Power Plants ◽  
Thermal Power ◽  
Pulverized Coal ◽  
Thermal Engineering ◽  
Thermal Power Plants ◽  
Pulverized Coal Combustion ◽  
Research Projects ◽  
Large Power ◽  
Combustion Processes

Paper presents short review of research problems, applied methods for solving problems and main results obtained by the researchers in Laboratory for Thermal Engineering and Energy (LTE) of the "Vinca" Institute of Nuclear Sciences, Belgrade, Serbia dealing with pulverized coal combustion processes and technologies for reduction of pollutions problems at thermal power plants in a period since 2000. The presented results were published in numerous studies realized for different users, Ph. D., Masters, and Specialist thesis, in international and domestic scientific journals and monographs, presented at numerous international and domestic scientific conferences, etc. Presented research projects and results of applied research projects realized at pulverized coal combustion thermal power plants clearly show that LTE team was involved in key activities of rehabilitation and modernization, including implementation of best available technologies for pollution reduction at thermal power plants, in the region of South East Europe.

scholarly journals Exergy efficiency analysis of lignite-fired steam generator

2018 ◽  
Vol 22 (5) ◽  
pp. 2087-2101
Author(s):  
Drenusha Krasniqi-Alidema ◽  
Risto Filkoski ◽  
Marigona Krasniqi
Keyword(s):  
Steam Generator ◽  
Flue Gas ◽  
Power Plants ◽  
Thermal Power ◽  
Calorific Value ◽  
Feed Water ◽  
Low Grade ◽  
Gas Temperature ◽  
Steam Generators ◽  
Energy And Exergy

The operation of steam generators and thermal power plants is commonly evaluated on a basis of energy analysis. However, the real useful energy loss cannot be completely justified only by the First law of thermodynamics, since it does not differentiate between the quality and amount of energy. The present work aims to give a contribution towards identification of the sources and magnitude of thermodynamic inefficiencies in utility steam generators. The work deals with a parallel analysis of the energy and exergy balances of a coal-fired steam generator that belongs to a 315 MWe power generation unit. The steam generator is de-signed for operation on low grade coal - lignite with net calorific value 6280 to 9211 kJ/kg, in a cycle at 545?C/177.4 bar, with feed water temperature 251?C, combustion air preheated to 272?C and outlet flue gas temperature 160?C. Since the largest exergy dissipation in the thermal power plant cycle occurs in the steam generator, energy, and exergy balances of the furnace and heat exchanging surfaces are established in order to identify the main sources of inefficiency. On a basis of the analysis, optimization of the combustion and heat transfer processes can be achieved through a set of measures, including retrofitting option of lignite pre-drying with flue gas and air preheating with dryer exhaust gases.

scholarly journals Fuel consumption of thermal power technologies under maneuvering modes

2020 ◽  
Vol 2020 (4) ◽  
pp. 45-49
Author(s):  
V.S. Kobernik ◽  
Keyword(s):  
Power Systems ◽  
Fuel Consumption ◽  
Fluidized Bed ◽  
Thermal Energy ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Power ◽  
Electric Energy ◽  
Coal Fuel ◽  
Fluidized Bed Boilers

A characteristic feature of the present day development of power engineering lies in the increase in the unevenness of power systems schedules. The structure of generating powers of Ukrainian energy engineering is overloaded with basic powers and characterized by a sharp deficit of maneuvering wanes. To cover the uneven load of the power system during the operation of existing and construction of new power plants, it is necessary to take into account the possibility of their operation under maneuvering modes. This paper determines the influence of work of power plants i under maneuvering modes on the specific consumption of conditional fuel on the released electric energy at working on gas or coal fuel. Fuel consumption for starting of a unit depends on its type and downtime in reserve. The use of steam–and–gas facilities and gas turbines helps to enhance the maneuverability of power plants. Alternative options for the development of thermal energy are the introduction of gas–piston power plants and power units with fluidized–bed boilers. We present formulas for the calculations of fuel consumption on by power units for start–ups and specific consumptions depending on the load and degree of their involvement to regulating loads for different thermal energy technologies: steam–turbine condensation and district heating power units; steam–and–gas and gas turbine plants; gas piston installations; power units with fluidized bed boilers. For enhancing the maneuverability of power plants, working on fossil fuels, their modernization and renewal of software are necessary. Quantitative assessment of the efficiency of power units and separate power plants during their operation under variable modes is important for forecasting the structure of generating capacities of power systems, the need to introduce peak and semi–peak capacities, the choice of the most profitable composition of operating equipment at different schedules of electrical loads Keywords: thermal power, power unit, maneuverable mode, electrical load, specific fuel consumption

scholarly journals Ash From Thermal Power Plants as Secondary Raw Material

2007 ◽  
Vol 58 (2) ◽  
pp. 233-238 ◽  
Author(s):  
Vladica Čudić ◽  
Dragica Kisić ◽  
Dragoslava Stojiljković ◽  
Aleksandar Jovović
Keyword(s):  
Power Plants ◽  
Negative Impact ◽  
Thermal Power ◽  
Raw Material ◽  
Low Grade ◽  
Thermal Power Plants ◽  
Heating Value ◽  
Prevention Programmes ◽  
Secondary Raw Material ◽  
The Republic

Ash From Thermal Power Plants as Secondary Raw MaterialThe basic characteristic of thermal power plants in the Republic of Serbia is that they use low-grade brown coal (lignite) as a fuel. Depending on the location of coal mines, lignite may have different properties such as heating value, moisture, and mineral content, resulting in different residue upon combustion. Because of several million tonnes of ash and slag generated every year, their granularmetric particle size distribution, and transport and disposal methods, these plants have a negative impact on the environment. According to the waste classification system in the Republic of Serbia, ash and slag from thermal power plants are classified as hazardous waste, but with an option of usability. The proposed revision of waste legislation in Serbia brings a number of simple and modern solutions. A procedure is introduced which allows for end-of-waste criteria to be set, clarifying the point where waste ceases to be waste, and thereby introducing regulatory relief for recycled products or materials that represent low risk for the environment. The new proposal refocuses waste legislation on the environmental impacts of the generation and management of waste, taking into account the life cycle of resources, and develops new waste prevention programmes. Stakeholders, as well as the general public, should have the opportunity to participate in the drawing up of the programmes, and should have access to them.

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