Improvement of existing coal fired thermal power plants performance by control systems modifications

This paper presents possibilities of implementation of advanced combustion control concepts in selected Western Balkan thermal power plant, and particularly those based on artificial intelligence as part of primary measures for nitrogen oxide reduction in order to optimise combustion and to increase plant efficiency. Both considered goals comply with environmental quality standards prescribed in large combustion plant directive. Due to specific characterisation of Western Balkan power sector these goals should be reached by low cost and easily implementable solution. Advanced self-learning controller has been developed and the effects of advanced control concept on combustion process have been analysed using artificial neural-network based parameter prediction model. (c) 2013 Elsevier Ltd. All rights reserved

Velocity measurements and flow structure visualizations of a self-sustained oscillating jet

The purpose of this study is the experimental investigation on self-sustained oscillating jet characteristics. Main aim was to describe vertical structures of turbulent air jet issuing from the nozzle of special configuration modified by the controlled oscillations in free jet setup. In the present experiments was used so-called "whistler nozzle", a simple-structured device capable to induce self-sustained excitations with controllable frequencies depending on the nozzle geometrical configuration. The frequency of the excitation measured with a far-field condenser microphone probe was around 1-2 kHz. The jet Reynolds number was in the range 48,000-95,000 in all experimental conditions presented in this paper. Flow field velocity measurements were provided in the free jet setup, with and without self-sustained excitations. The images of both free and impinging jets were taken with a high-speed digital video camera. The flow field and structure of the jet were found to be extremely sensitive to the excitation and dependent on the excitation conditions. This fact can lead to the conclusion that the local heat transfer characteristics of jet impingement are also remarkably dependent on the jet excitation

Wind Power Plant Resilience

A wind energy system transforms the kinetic energy of wind into mechanical or electrical energy that can be harnessed for practical use. Mechanical energy is most commonly used for pumping water in rural or remote locations. Electrical energy is obtained by connecting wind turbine with the electricity generator. The performance of the wind power plant depends on the wind kinetic energy. It depends on the number of design parameter of the wind turbine. For the wind power plant the wind kinetic energy conversion depends on the average wind velocity, mechanical energy conversion into electricity, and electricity transmission. Resilience of the wind power plant is the capacity of the system to withstand changes of the following parameters: wind velocity, mechanical energy conversion into electricity, electricity transmission efficiency a and electricity cost. Resilience index comprise following indicators: change in wind velocity, change in mechanical energy conversion efficiency, change in conversion factor. change in transmission efficiency, and change in electricity cost. The demonstration of the resilience index monitoring is presented by using following indicators, namely: average wind velocity, power production, efficiency of electricity production, and power-frequency change. In evaluation of the resilience index of wind power plants special attention is devoted to the determination of the resilience index for situation with priority given to individual indicators

Modeliranje turbulentnog dvofaznog toka aero-smeše sprašenog uglja u gorioničkim kanalima sa jednostepenim turbulatorima

The subject of this work is turbulent two-phase flow through air-coal channel(s) of complex geometry. The aim of this work is numerical optimization of fluid flow and coal particle distribution in reconstructed air-coal mixture channels. The single blade turbulator has been used to increase turbulence in the vertical section of an air-coal mixture channel. Standard k-ω turbulent model has been used for modeling turbulence. Lagrangian multiphase model has been used for discrete phase (coal particles) modeling. Although better particle distribution is reached using single blade turbulators, particle concentration in the evaluation section (where plasma generators will be built in) still remains anisotropic. Because uniform coal particle distribution is of great importance for the proper work of plasma generators, other solutions for achieving this goal will be the object of the future analysis.Predmet ovog rada je turbulentno dvofazno strujanje kroz gorioničke kanale aero-smeše sprašenog uglja kompleksne geometrije. Cilj ovog rada je numerička optimizacija strujnog toka i raspodele čestica sprašenog uglja u rekonstruisanim gorioničkim kanalima. Za povećanje turbulencije, u vertikalnom delu gorioničkog kanala aero smeše ugrađen je jednostepeni turbulator. Za modeliranje turbulencije korišćen je standardni k-ω turbulentni model. Lagranžeov pristup je korišćen za modeliranje sekundarne faze (čestica sprašenog uglja). Iako je upotrebom jednostepenih turbulatora postignuta bolja raspodela čestica sprašenog uglja, koncentracija čestica u prelaznom delu (u kome će biti ugrađeni plazma generatori) ostaje neravnomerna. Kako je ravnomerna raspodela čestica sprašenog uglja od esencijalnog značaja za pravilan rad plazma generatora, druga rešenja za postizanje ravnomerne raspodele čestica će biti predmet buduće analize

Variability of carbon emission factors from lignite of the Kostolac basin in time

This paper presents experimental tests of lignite from the Kostolac open-pit mine, used to operate the boiler of the Kostolac B2 thermal power plant in 2022. Experimental tests were conducted to determine the emission characteristics and carbon emission factor and compare these values with those taken and determined in 2016. A total of 31 samples taken in April 2022 were tested. As with our previous work, the experimental methodology includes proximate analysis, ultimate analysis and determination of calorific value, for the 'as received', 'as determined' and dry basis. Corresponding correlations were established for the tested Kostolac lignite. The emission characteristics of the Kostolac lignite from 2022 were compared with the corresponding values from 2016. Certain changes in the values of the carbon emission factor over time are a regular phenomenon and therefore periodic sampling and experimental determinations are inevitable to follow the changes in the values. For this change in coal properties, new values for the carbon emission factor are proposed, which should be used to calculate the total carbon dioxide emissions in the last period

Numerical modeling of disperse material evaporation in axisymmetric thermal plasma reactor

A numerical 3D Euler-Lagrangian stochastic-deterministic (LSD) model of two-phase flow laden with solid particles was developed. The model includes the relevant physical effects, namely phase interaction, panicle dispersion by turbulence, lift forces, particle-particle collisions, particle-wall collisions, heat and mass transfer between phases, melting and evaporation of particles, vapour diffusion in the gas flow. It was applied to simulate the processes in thermal plasma reactors, designed for the production of the ceramic powders. Paper presents results of extensive numerical simulation provided (a) to determine critical mechanism of interphase heat and mass transfer in plasma flows, (b) to show relative influence of some plasma reactor parameters on solid precursor evaporation efficiency: 1 - inlet plasma temperature, 2 - inlet plasma velocity, 3 - particle initial diameter, 4 - particle injection angle a, and 5 - reactor wall temperature, (c) to analyze the possibilities for high evaporation efficiency of different starting solid precursors (Si, Al, Ti, and B2O3 powder), and (d) to compare different plasma reactor configurations in conjunction with disperse material evaporation efficiency

Improvement of environmental aspects of thermal power plant operation by advanced control concepts

The necessity of the reduction of greenhouse gas emissions, as formulated in the Kyoto Protocol, imposes the need for improving environmental aspects of existing thermal power plants operation. Improvements can be reached either by efficiency increment or by implementation of emission reduction measures. Investments in refurbishment of existing plant components or in plant upgrading by flue gas desulphurization, by primary and secondary measures of nitrogen oxides reduction, or by biomass co-firing, are usually accompanied by modernisation of thermal power plant instrumentation and control system including sensors, equipment diagnostics and advanced controls. Impact of advanced control solutions implementation depends on technical characteristics and status of existing instrumentation and control systems as well as on design characteristics and actual conditions of installed plant components. Evaluation of adequacy of implementation of advanced control concepts is especially important in Western Balkan region where thermal power plants portfolio is rather diversified in terms of size, type and commissioning year and where generally poor maintenance and lack of investments in power generation sector resulted in high greenhouse gases emissions and low efficiency of plants in operation. This paper is intended to present possibilities of implementation of advanced control concepts, and particularly those based on artificial intelligence, in selected thermal power plants in order to increase plant efficiency and to lower pollutants emissions and to comply with environmental quality standards prescribed in large combustion plant directive. [Acknowledgements. This paper has been created within WBalkICT - Supporting Common RTD actions in WBCs for developing Low Cost and Low Risk ICT based solutions for TPPs Energy Efficiency increasing, SEE-ERA.NET plus project in cooperation among partners from IPA SA - Romania, University of Zagreb - Croatia and Vinca Institute from Serbia and. The project has initiated a strong scientific cooperation, with innovative approaches, high scientific level, in order to correlate in an optimal form, using ICT last generation solutions, the procedures and techniques from fossil fuels burning processes thermodynamics, mathematical modelling, modern methods of flue gases analysis, combustion control, Artificial Intelligence Systems with focus on Expert Systems category.

Thermodynamic equilibrium modeling of biomass gasification: Effects of operating conditions on gasifier performance

Biomass has remarkable potential to reduce harmful emissions and ensure stable and sustainable energy production. In this paper, various parameters such as operating temperature, type of gasifying agent, air–fuel ratio and steam-fuel ratio are investigated on the qualitative characteristics of the syngas obtained from biomass gasification. The qualitative indicators considered were the percentage of combustible components under the energy aspect and the percentage of undesirable components under the environmental aspect. The composition of the syngas was determined for a temperature range of 500–1000 °C as an equilibrium composition using the Gibbs free energy minimisation method. The results showed that increasing the gasification temperature above 900 °C had a positive effect on the energy and environmental properties of the syngas. Air and water vapour were selected as possible gasifying agents. The results showed that water vapour was significantly more favourable than air as a gasifying agent in terms of syngas quality. In the best case, the H2 yield for gasification with air is 35 %vol, while this value reaches 65 %vol for gasification with steam. In addition to the type, the ratio of the gasifying agent to the amount of fuel was also analysed. The analysis showed that it was more favourable to carry out the gasification process at lower air-to-fuel and steam-to-fuel ratios, which is consistent with the work of other authors

Hazardous waste management and suitable waste-to-energy conversion technologies in the Republic of Serbia

Population growth, consumerism, and industrial development have led to the increased hazardous and solid municipal waste amounts worldwide. Incineration, gasification, pyrolysis, smelting, or glazing have been proposed to treat the hazardous waste before disposal in inert soil. This paper discusses the management of hazardous waste, proper legislation treating this field, the quantity of the hazardous waste substances, and energy production potentials from this type of waste materials in the territory of the Republic of Serbia. This paper gives an overview of the available thermal treatment methods and waste-to-energy technologies in terms of their performance and environmental impact suitable for the Republic of Serbia. The analysis showed that proper development of this industrial sector could contribute to increased opportunities for new jobs to help mitigation of environmental issues, which will significately improve overall Serbian economy.Rast populacije, konzumerizam i industrijski razvoj doveli su do povećanja količine opasnog otpada i čvrstog komunalnog otpada širom sveta. Za tretiranje opasnog otpada pre odlaganja na intertno tlo predloženi su insineracija, gasifikacija, piroliza, topljenje i zastakljivanja. U ovom radu razmatra se upravljanje opasnim otpadom, odgovarajuća zakonska regulativa na ovom polju, količina opasnih otpadnih materija i potencijali za proizvodnju energije iz ove vrste otpada na teritoriji Republike Srbije. U radu je dat pregled raspoloživih metoda termičke obrade i tehnologija za proizvodnju energije iz otpada u pogledu njihovih performansi i uticaja na životnu sredinu, shodno uslovima u Republici Srbiji. Analizom je pokazano da bi pravilan razvoj razmatranog industrijskog sektora mogao pružiti mogućnost za nova radna mesta u cilju ublažavanja ekoloških problema, što bi takođe moglo da unapredi privredu Republike Srbije.Power Plants 2021 : Elektrane 2021; November 17-18, 2021, Belgrade, Serbi

Determination of the average annual efficiency by adapted measurement procedure on CHP plants

The paper presents the methodology for the determination of the average annual efficiency of CHP plants. The method is based on determining the effective efficiency on three different loads in order to obtain a functional dependence of the efficiency and unit load. For the calculation of the average annual efficiency, the annual load of the plant and the calculated functional dependence of the efficiency are taken into account. When calculating the effective efficiency, both methods, direct and indirect, were used. The methodology for determining the average annual efficiency of the CHP plant was implemented on the example of the cogeneration gas power plant "VELEBIT 3B" within the petroleum company NIS, Serbia. The presented methodology can be applied to similar plants for the determination of average annual efficiency.Power Plants 2021 : Elektrane 2021; November 17-18, 2021, Belgrade, Serbi