scholarly journals A study on the grindability of Serbian coals

2011 ◽  
Vol 15 (1) ◽  
pp. 267-274 ◽  
Author(s):  
Dejan Radic ◽  
Marko Obradovic ◽  
Miroslav Stanojevic ◽  
Aleksandar Jovovic ◽  
Dragoslava Stojiljkovic

Thermal power plants in the Republic of Serbia are making considerable efforts and even more considerable investments, not only to maintain electricity production at maximum design levels, but even to additionally increase the power output of existing generating units. Capacities of mills used in pulverized coal preparation are identified as one of the main constraints to achieving maximum mill plant capacity, while coal grindability is seen as one of the factors that directly affect capacities of the coal mills utilized in thermal power plants. The paper presents results of experimental investigation conducted for the purpose of determining Hardgrove grindability index of coal. The investigation was conducted in accordance with ISO 5074 and included analysis of approximately 70 coal samples taken from the open pit mine of Kolubara coal basin. Research results obtained indicate that coal rich in mineral matter and thus, of lower heating value is characterized by higher grindability index. Therefore, analyses presented in the paper suggest that characteristics of solid fuels analyzed in the research investigation conducted are such that the use coals less rich in mineral matter i. e. coals characterized by lower grindability index will cause coal mills to operate at reduced capacity. This fact should be taken into account when considering a potential for electricity production increase.

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Tomislav M. Pavlović ◽  
Ivana S. Radonjić ◽  
Dragoljub Lj. Mirjanić ◽  
Darko Divnić

The paper provides information on renewable energy sources (RES) and legislation related to the RES generated electricity in Serbia and the Republic of Srpska. In Serbia, hydropower, wind energy, solar energy, biomass and biogas are used for the RES generated electricity, whereas hydropower, solar energy, biomass and biogas are utilized in the Republic of Srpska. The paper gives an overview of the power of RES power plants and the percentage share of the thermal power plants and RES power plants in electricity production and the guaranteed (incentive) prices for RES generated electricity in Serbia and the Republic of Srpska. Furthermore, legal regulations related to the production of electricity from RES in Serbia and the Republic of Srpska are given. In the conclusion, it is pointed out that RES is increasingly used in Serbia and the Republic of Srpska for the production of electricity, that there are appropriate legal regulations and guarantees (incentive prices) for electricity generated by RES power plants.


2019 ◽  
Vol 124 ◽  
pp. 01040 ◽  
Author(s):  
D. T. Nguen ◽  
D. N. Pham ◽  
G. R. Mingaleeva ◽  
O. V. Afanaseva ◽  
P. Zunino

The growing demand for energy and fossil fuels creates increased number of difficulties, while renewable energy sources are still rarely used worldwide, particularly in Vietnam. In this article hybrid thermal power plants based on gas turbine plants are discussed, the increased efficiency of which is achieved by air heating after the compressor in solar air heaters. The basic design equations and the results of evaluating the efficiency and fuel consumption are presented for two thermal power plants of 4.6 MW and 11.8 MW. The dependence of the results on the intensity of solar extraction for the climatic conditions of the Ninh Thuan province of the Republic of Vietnam is discussed.


The paper is devoted to analysis of functional peculiarities of thermal power plants in Ukraine. In the course of the study, key determinants of the sustainable development of domestic electricity generation were identified in the context of transition to a new market model. The preconditions of activation and support of the sustainable development concept implementation process in the modern business practice of the energy sector enterprises within the Ukrainian economy are outlined. The theoretical and practical bases for ensuring the sustainable development of energy in relation to other United Nations Declarations of Sustainable Development are indicated. The comparative estimation of the efficiency level of state policy in scope of energy independence and resource conservation with the use of a complex indicator of GDP energy intensity is given. On the basis of international and domestic statistical data the dynamics of volumes of electricity production in Ukraine for the period of 1990-2017 as well as the structure of electricity generation by type of generation were analyzed. The dynamics of electric power generation in Ukraine by types of raw materials was presented in complex with the dynamics of coal consumption and production for the corresponding period. The peculiarities of thermal power plants functioning in comparison with other power generating enterprises in modern conditions are specified. The key element of Ukraine’s energy independence – the volume of proven coal reserves – is a prerequisite for the efficient functioning of domestic thermal power plants. The pricing features in the sphere of electricity production and sales are outlined, in particular, the structure of market rate and the price of electricity sales by producers to the Wholesale Market are presented. The significance of the innovation factor in the process of improving the efficiency of thermal power plants functioning has been substantiated, taking into account the economic, social and environmental aspects of their production and economic activity.


2007 ◽  
Vol 58 (2) ◽  
pp. 233-238 ◽  
Author(s):  
Vladica Čudić ◽  
Dragica Kisić ◽  
Dragoslava Stojiljković ◽  
Aleksandar Jovović

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.


Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7136
Author(s):  
Andrey Rogalev ◽  
Vladimir Kindra ◽  
Ivan Komarov ◽  
Sergey Osipov ◽  
Olga Zlyvko

The Rankine cycle is widely used for electricity production. Significant weight and size characteristics of the power equipment working on superheated steam are the main disadvantages of such power plants. The transition to supercritical carbon dioxide (S-CO2) working fluid is a promising way to achieve a significant reduction in equipment metal consumption and to increase energy efficiency. This paper presents the results of thermodynamic analysis of S-CO2 thermal power plants (TPPs) utilizing the heat of combustion products of an energy boiler. It was found that the net efficiency of the developed S-CO2 TPP with a pulverized coal-fired boiler reached 49.2% at an initial temperature of 780 °C, which was 2% higher compared to the efficiency level of steam turbine power plants (STPPs) at a similar turbine inlet temperature.


Author(s):  
Parakram Pyakurel ◽  
Filipe Quintal ◽  
James Auger ◽  
Julian Hanna

One method of reducing atmospheric CO2 emissions in the transportation sector is the replacement of conventional fossil fuel-based vehicles with Electric Vehicles (EVs). However, fossil fuels are still the primary source of electricity production in many regions and the utilization of EVs in such regions increases the electricity demand because of battery charging. This results in increased burning of fossil fuels by thermal power plants and therefore can offset savings in CO2 emissions resulting from the adoption of EVs. In this paper, we consider a scenario where all fossil fuel-based conventional vehicles are replaced by EVs and then estimate the net CO2 emission savings resulting from the adoption of EVs in a region where electricity is primarily supplied by thermal plants. Only emissions generated during the operational phase of vehicle use are considered; emissions during the production phase are not considered. The region under consideration is Madeira, Portugal where thermal plants account for 80% of the total electricity produced. Our findings suggest that although EVs have huge potential to save CO2 emissions, a substantial amount of the savings can be offset due to the increased burning of fossil fuels by thermal plants to meet the electrical demand of charging batteries.


2012 ◽  
Vol 16 (2) ◽  
pp. 605-612
Author(s):  
Slavko Djuric ◽  
Petko Stanojevic ◽  
Dragan Djuranovic ◽  
Sasa Brankov ◽  
Srdjan Milasinovic

In this paper we have looked into the qualitative analysis of coals in Bosnia and Herzegovina (B-H). The analysis includes the following characteristics: moisture (W), ash (A), combustible matter (Vg) and lower heating value (Hd). From the statistic parameters we have determined: absolute range (R), arithmetic mean (X), standard deviation (S) and variations coefficient (Cv). It has been shown that the coal characteristics (W, A, Vg, Hd) have normal distribution. The analysis show that there are considerable deviations of ash characteristics: moisture (36.23%), ash (34.21%), combustible matter (16.15%) and lower heating value (25.16%) from the mean value which is shown by the variations coefficient (Cv). Large oscilations of mass portions: W, A, Vg and Hd around the mean value can adversely influence the function of a boiler plant and an electric filter plant in thermal power plants in B-H in which the mentioned types of coal burn. Large ash oscilations (34.21%) around the mean value point out to the inability of application of dry procedures of desulphurisation of smoke gasses (FGD) due to the additional quantity of ash. It has been shown that the characteristics of Bosnian types of coal do not deviate a lot from the characteristics of coal in the surrounding countries (coals of Serbia and Monte Negro). The results can be used in analysis of coal combustion in thermal power plants, optimisation of electrical-filtre, reduction of SO2 in smoke gas and other practical problems.


In thermal power plants, the boiler feed pumps are classified as vital machines. Therefore, the lack of its availability leads immediately to a loss of electricity production. They can also be the source of serious incidents or accidents that directly threaten the operational safety of the machine, as well as the safety of personnel. The inspection is a very effective solution to reduce the possibility of an accident. The vibration analysis can specifically detect with opportunity the possible mechanical, hydraulic and electrical defects that probably exist in motor pump. This document presents different techniques of vibration analysis, which were applied in different pumps to make an effective diagnosis.


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5848
Author(s):  
Guzel Mingaleeva ◽  
Olga Afanaseva ◽  
Duc Toan Nguen ◽  
Dang Nayt Pham ◽  
Pietro Zunino

The article describes a method of integrating small distributed generation components in the power system of the Republic of Vietnam. The features of the energy system of Vietnam and the technologies used for mini thermal power plants are considered. The classification of small distributed generation components is presented with implantation of the most used resources of Vietnam—fossil and renewable. A generalized methodology for selection and calculation of technological schemes for mini thermal power plants is considered. The schemes of steam-turbine mini thermal power plants operating with coal and gas-turbine mini thermal power plants with solar air heaters are selected. Based on the calculation of the selected mini thermal power plant schemes, their distribution in the territory of the Republic of Vietnam has been obtained. The thermoeconomic efficiency has been chosen as the criterion for the best option for placing mini thermal power plants; its value for the proposed option is of 6.77%.


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