Coal-fired Thermal Power Plants Research Articles

Numerical simulation of the heat transfer characteristics of the second and third superheaters in a coal-fired thermal power plant boiler

Numerical simulation of the heat transfer characteristics of the second and third superheaters in a coal-fired thermal power plant boiler

Numerical simulation of the thermal radiation and convective heat transfer characteristics of the second superheater in a coal-fired thermal power plant boiler

Superheaters are critical components in a coal-fired power plant because they sustain the highest tube wall (metal) temperature point in the boiler. The pressurized steam flowing in superheater tubes is mainly heated via the thermal radiation and convection from the combustion gas in the radiant zone. To prevent the bursting of superheater tubes caused by the high-temperature creep, corrosion, and thermal fatigue for proper plant operation and maintenance, accurately predicting complex heat transfer characteristics, estimating the local temperature, and assessing the heat flux of the superheater are essential. In this study, a computational fluid dynamics model of the boiler and the superheater in a coal-fired power plant was developed using radiation and turbulence models. The local metal temperature and heat flux of the superheater were evaluated by calculating the heat exchange between the combustion gas and pressurized steam flows in the tubes. The calculated values of the steam outlet temperature accurately matched the values measured using the equipment at the plant, and thermal radiation was confirmed to be dominant in the boiler. The metal temperature and heat flux of the superheater at the outermost heat transfer tubes, which receive the maximum thermal radiation, were larger than those of the superheater at the inner tubes. Therefore, the outermost tubes were determined to be under the most severe thermal conditions despite having a higher mass flow rate of steam. Additionally, the heat fluxes on the center lines of superheater tube panels were higher due to the large gap between the adjacent heat transfer tubes at the bent part.

Errata: Numerical simulation of the thermal radiation and convective heat transfer characteristics of the second superheater in a coal-fired thermal power plant boiler [Mechanical Engineering Journal, Vol. 9, No. 4 (2022), 22-00040

Errata: Numerical simulation of the thermal radiation and convective heat transfer characteristics of the second superheater in a coal-fired thermal power plant boiler [Mechanical Engineering Journal, Vol. 9, No. 4 (2022), 22-00040

Оптимальне завантаження генеруючих потужностей енергосистеми за умови експлуатації сонячних електростанцій із системами акумулювання

Due to the increase in the share of electricity production at solar photovoltaic power plants (PV-plants), with a decrease in consumption and low flexibility of the power system, forced dispatch restrictions of generating capacities are already occurring. The problem of the emergence of a power surplus with an increase in the capacity of PV-plant can be solved by introducing a battery energy storage system (BESS) into its structure. The purpose of this study is to develop a mathematical model for the joint operation of a PV-plant and BESS for the formation of characteristic hourly daily power profiles for the supply of electrical energy to the power system. With the subsequent assessment of the impact of such hybrid PV-plants on changing the loading modes of traditional generating capacities in the Integrated power system of Ukraine. The proposed mathematical model for the joint operation of a PV-plant and BESS is, in fact, an algorithm for controlling such a hybrid PV-plant. The main principle of which is that during the period of maximum solar irradiation, the batteries are charged to the maximum possible level, which corresponds to the available capacity, and if the volume of BESS produced at the PV-plant is less than the available capacity, then all the generated electrical energy is accumulated for further discharge. Thus, the main modes of joint operation of a PV-plant and BESS are distinguished: mode No. 1 – when all PV generated electrical energy is charged with subsequent discharge; mode No. 2 – only a part of PV generated electrical energy is transferred in time, and the other part is supplied to the power system directly. Based on the developed mathematical model, daily profiles were formed for the joint operation of a PV-plant and BESS for a whole year. The analysis of the obtained daily profiles for the whole year showed, that for a day with maximum solar irradiation, in order to transfer 20% of PV-plants generated electrical energy, the discharge power of the BESS should be about 37% of the installed capacity of the inverters of the PV-plants. Thus, for 2040, with the installed capacity of PV-plants at the level of 11 GW, the total capacity of BESS should be 4 GW, and their charging capacity – 16 GWh. Using a mathematical programming model, determining the optimal structure and loading of power units of the power system when covering the daily schedule of electrical loads for each day of the year, it was determined that the introduction of BESS in PV-plants affects the performance of the power system as a whole. The transfer of 20% of the peak generation capacity of PV-plants with an installed capacity of 11 GW at the level of 2040 leads to: an increase in the production of electricity from nuclear power plants by 8% with an increase in the number of power units with an installed capacity of 1000 MW; the volume of electricity production at coal-fired thermal power plants is reduced by 20%; the generation volumes of pumped storage power plants are reduced by 4.5% and the discharge volumes of the system-scale storage systems are reduced by 57%. Reducing coal consumption by 19% leads to a 15‒19% reduction in emissions of carbon dioxide, sulfur oxides, nitrogen oxides and dust, which are important results for achieving environmental goals of Ukraine. Keywords: structure of generating capacities, power system, PV-plant, battery energy storage system, mathematical model

The Global Environmental Agenda of 2021 and the tasks of sustainable energy-ecological development and cooperation between Japan and countries Southeast Asia

The article discusses the main results of two major international summits held in October-November 2021, the key topics of which were the issues of the global fight against climate change and environmental protection. The decisions taken at these conferences, with the broad participation of world leaders, reflect the fundamental trends of the global environmental agenda. Within the framework of this agenda, Japan and the countries of Southeast Asia are building their modern energy and environmental cooperation. In this context, the article examines the main urgent tasks of energy-environmental interaction and sustainable development of Japan and the states of Southeast Asia. These countries are located in the Asia-Pacific region, which remains until now the main emitter of greenhouse gases in the world. However, the indicators of environmental pollution by Japan and the Southeast Asian countries are relatively not so high, compared to some other states in the region and the world. The article discusses the most relevant and significant examples of bilateral and multilateral cooperation between these countries in areas related to curbing global warming and climate protection. It has been revealed that with all the efforts made, since the 1990s, the indicators of reducing harmful emissions into the atmosphere in Japan remain modest and even lag behind some of the Western countries. The Southeast Asian countries show a serious attitude to the development of renewable energy, but their intention to abandon coal still raises some doubts about the methods of implementing this ambitious plan. In particular, it is currently not entirely clear whether these countries are preparing to make a full-fledged "energy transition" in the coming decades, or whether they just intend to replace their coal-fired thermal power plants with gas ones.

Analysis of suitability of TPP ash-slag waste as materials for hydrogen fuel storage

The current trends in energy were described, the main of which is the use of alternative energy sources, especially hydrogen. The most common methods of hydrogen accumulation were proposed: accumulation of compressed gaseous hydrogen in high-pressure tanks; accumulation of liquid hydrogen in cryogenic tanks; storing hydrogen in a chemically bound state; accumulation of gaseous hydrogen in carriers with a high specific surface area. Based on the combination of advantages and disadvantages, the most promising methods of accumulation were selected: storage of liquid hydrogen and storage of hydrogen in carriers with a high specific surface area. The main requirement for materials for hydrogen storage by these methods was revealed – a high specific surface area. Prospects for the development of waste-free low-emission technologies due to the recycling of secondary raw materials and the development of low-temperature technologies for the synthesis of functional and structural materials were substantiated. The applicability of large-scale ash and slag waste from coal-fired thermal power plants as a raw material for obtaining materials by low-temperature technologies was shown. The traditional ways of using ash and slag waste as a raw material, active additive and filler in the production of cements were described. Modern technologies for the production of innovative materials with a unique set of properties were presented, namely carbon nanotubes, silica aerogel and geopolymer materials. The prospect of using geopolymer matrices as a precursor for the synthesis of a number of materials was described; the most promising type of materials was selected – geopolymer foams, which are mainly used as sorbents for purifying liquids and gases or accumulating target products, as well as heat-insulating materials. The possibility of obtaining products of any shape and size on the basis of geopolymer matrices without high-temperature processing was shown. The special efficiency of the development of the technology of porous granules and powders obtained from a geopolymer precursor using various methods was substantiated. The obtained granules can be used in the following hydrogen storage technologies: direct accumulation of hydrogen in porous granules; creation of insulating layers for liquid hydrogen storage units.

Waste Heat Recovery From Fly Ash of 210 MW Coal Fired Power Plant Using Organic Rankine Cycle

Abstract Combustion of coal in thermal power plants generates ash as a residue, which depends on the quality of coal, specific to its ash content and calorific value. In a typical Indian scenario, a standard 210 MW thermal plant produces ∼57 T/hr total ash, which has 80:20 fly and bottom ash share, considering coal with 40% ash content. This study aims to harness the waste heat of fly ash collected at the bottom of the electrostatic precipitator (ESP) by coupling organic Rankine cycle (ORC) with 210 MW subcritical coal-fired thermal power plant works on R134a. Thermodynamic properties of R134a are taken from the PYroMAT library (python 3.6) to develop a computer-based program that estimates the variability of key parameters with respect to log mean temperature difference (LMTD). The main plant's efficiency was 28.714%, with main steam pressure, reheat pressure, and temperature being about 134.35 bar, 24.02 bar, and 540 °C, respectively, and combustion of coal is about 141.5 T/hr. The study shows additional generation from fly ash waste heat is about 30.5 kW with an increase in net power output (0.0145%) and net energy efficiency (0.0146%). The optimum value of LMTD for the evaporator, condenser, and recuperator is 40, 7, and 16 K, which yields the optimum energy efficiency and developed cost-effective design. The proposed system is economically analyzed, considering 25 years of equipment life and 14% of loan interest. The study shows that the payback period and the generation cost of electricity of ORC is about 6.22 years and INR 3.14 per kWh, respectively.

Оценка экологических последствий от объектов энергетики при реализации перспективных проектов освоения месторождений арктических территорий восточных регионов России

The ecological aspects of the functioning of energy facilities in the Arctic zones of the eastern regions of Russia are of increasing importance for the strategic interests of the country, on the one hand, and due to the specific features of territories with a weak ability to restore the natural environment, on the other hand. The studies carried out at the Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences revealed the fact that the current environmental situation in the eastern regions of the Arctic is unfavorable. Promising projects for the development of mineral deposits are associated with an increase in the consumption of all types of energy resources. In addition, this will require intensive development of the energy sector: from the expansion of existing power facilities to the construction of new ones using associated petroleum gas, and possibly LNG. In general, the implementation of projects will lead to the following distribution of the total emission of pollutants from the energy sector: 47% — the Taimyr-Turukhan zone, 30% — the North Yakutsk zone with a predominant contribution from coal-fired boilers, and, accordingly, 23% of all emissions will enter the atmosphere of the Chukotka zone, where coal-fired boiler houses also prevail. With the implementation of advanced development projects, CO2 emissions will also increase from 7 to 16.6 million tons with their predominance in the Taimyr-Turukhan zone (11,9 million tons). Thus, the assessment of the environmental impact from the development of promising deposits in the Arctic territories of the eastern regions of Russia has shown that the emissions of pollutants will increase by 1.6-1.8 times, and those of carbon dioxide by 2.2-2.3 times. Given that the particulate matter will remain the main impurity in the composition of pollutants (up to 35-37%) due to the existing power facilities, coal-fired thermal power plants and boiler houses need a large-scale modernization of the collection equipment. Sulfur dioxides are becoming another predominant impurity, mainly due to newly commissioned facilities running on associated petroleum gas. Therefore, it is necessary to envisage measures to reduce them.

Exergoeconomic and exergoenvironmental analysis of a coal-fired thermal power plant

Exergoeconomic and exergoenvironmental analysis of a coal-fired thermal power plant

Tintinnids (Ciliophora, Oligotrichea) within power plant discharge and marine protected areas in Masinloc-Oyon Bay

There are only five studies on tintinnids of the Philippines. We present a checklist of tintinnids (Ciliophora, Oligotrichea) from Masinloc-Oyon Bay, Province of Zambales, West Philippine Sea. Masinloc-Oyon Bay is a unique in having both marine protected areas and a coal-fired thermal power plant within the same bay. Field sampling was performed in July 2017, which recorded 10 species belonging to one order, six families, and seven genera. Station 1 inside the power plant’s outfall had the lowest diversity, whereas the stations within marine protected areas had a relatively higher species diversity index. Our new data are the first records of tintinnid species in Masinloc-Oyon Bay. These records add to the regional checklist of the Philippine Sea.

Analysis on Boiler Operation and Safety Performance of 300MW Coal-fired Thermal Power Plant

Analysis on Boiler Operation and Safety Performance of 300MW Coal-fired Thermal Power Plant

Evolutionary game theoretic study on the coordinated development of solar power and coal-fired thermal power under the background of carbon neutral

In recent years, China has been promoting the process of carbon neutral by establishing carbon exchanges (CEs) and implementing relevant carbon emission reward and punishment policies. This study proposes a partnership of the CE, solar power plant (SPP) and coal-fired thermal power plant (TPP). Based on the tripartite evolutionary game model and current policies of China, the evolutionary processes are simulated and discussed. The results reveal that stable states can be achieved under different partnership modes. Effect evaluation results of typical parameters on the three participants show that on the premise of ensuring the participations of CE and SPP, properly reducing the prices of carbon emission share sold to the TPP will strengthen the participation willingness of TPP. The relatively reasonable selling price ranges of carbon emission share of the CE and SPP sold to the TPP are 6.0∼6.2 $/t and 5.3∼5.5 $/t, respectively. Higher zero carbon emission reward and higher carbon tax can strengthen the participation willingness of TPP and make the TPP achieve the carbon neutral. This study can provide a reference for the government and related industries to promote the carbon neutral development as well as the coordinated development of solar power and coal-fired thermal power.

Research on the full-load joint regulation strategy of coal-fired generating units and electrolyzed hydrogen production

As the installed capacity of wind power and other renewable energy sources continues to increase, the intermittent and volatility of their output has put tremendous pressure on the safe and stable operation of the power grid. The demand for peak shaving is becoming increasingly urgent. In this paper, the electrolysis hydrogen production system participates in the deep peak shaving of coal-fired generators. Through the participation of load regulation of the electrolysis hydrogen production system, according to the requirements of the power grid on the different loads of the unit, the load of the electrolysis hydrogen production system is adjusted to adjust the load of the unit. In order to realize full-load regulation of coal-fired thermal power plants and improve the power generation efficiency of units.

Investigating the Palm Oil Mill Wastes Properties for Thermal Power Plants

Renewable energy is a reliable solution for addressing global warming and fossil fuel depletion issues. Due to the abundance of biomass resources, such as palm oil wastes, which are currently underutilised, this is an opportunity for Malaysia to seize and implement this renewable energy solution for power generation. Palm oil mill wastes, such as empty fruit bunch (EFB), palm mesocarp fibre (PMF), and palm kernel shell (PKS), are worth to be investigated as a possible feedstock for combustion in thermal power plants. Co-combustion or co-firing of biomass in coal-fired thermal power plants offers a significant potential to reduce harmful emissions and represents a low cost and low-risk method. This paper aims to review and compare existing biomass thermal combustion technologies globally to evaluate the potential of utilising palm oil waste with coal. Before undergoing various pretreatment options, it is necessary to understand the feedstock characteristics for thermal power plant combustion. It is recommended to implement the combustion of palm oil wastes with coal in Malaysia to reduce harmful pollution. Based on the findings, Malaysia appears to be on the right track to optimise the use of palm oil wastes for electricity generation. The enhanced usage will reduce the negative impact of greenhouse gas (GHG) emissions.

Sulfur and Nitrogen Oxides in the Atmosphere of Lake Baikal: Sources, Automatic Monitoring, and Environmental Risks

This paper analyzes the results of the automatic (in situ) recording of the regional transport of pollutants from the large regional coal-fired thermal power plants in the atmospheric boundary layer above the southern basin of Lake Baikal. Due to high stacks (about 200 m), emissions from large thermal power plants rise to the altitudes of several hundreds of meters and spread over long distances from their source by tens and hundreds of kilometers. The continuous automatic monitoring of the atmosphere in the southern basin of Lake Baikal on top of the coastal hill (200 m above the lake) revealed the transport of a large number of sulfur oxides and nitrogen oxides in the form of high-altitude plumes from thermal power plants of the large cities located 70 to 100 km to the northwest of the lake (Irkutsk and Angarsk). The consequence of such transport is the increased acidity of precipitation in the southern basin of Lake Baikal and the additional influx of biogenic nitrogen compounds to the lake ecosystem. The spatial scale and possible risks of such regional transport of air pollution for the lake ecosystem require further closer study.

Variability in air-pollutants, aerosols, and associated meteorology over peninsular India and neighboring ocean regions during COVID-19 lockdown to unlock phases

The study focuses on the variability in aerosols, air-pollutants, and associated meteorological characteristics over peninsular India and neighboring ocean regions during both lockdown (25 March-31 May) and unlock (June–September) periods in 2020. During first lockdown phase, 40–60% reduction in aerosol loading observed over most parts except central-west India and the southern BOB. HYSPLIT model-based ‘back trajectory’ suggests the increase in anthropogenic aerosols over BOB due to long-range transport from an elevated layer. During second lockdown phase, an increase in AOD found over the eastern parts of India might come from the continuous operation of coal-fired thermal power plants and coal mines, besides domestic emissions. A surge in sea salt aerosols over BOB during the last two lockdown phases could be due to the Amphan super cyclone. During unlock phases, only natural aerosols show significant variation over the coastal and neighboring ocean regions with the simultaneous presence of intense summer monsoon. However, anthropogenic aerosols increased over the inland areas, which is most prominent in second and fourth unlock phases and could be attributed to the long-range transport. Temporal analysis of particulate matters and gaseous pollutants over coastal cities suggests Ahmedabad to be the most polluted one. The highest fall in NO2 was observed over Mumbai, whereas O3 concentration was appreciably enhanced over Ahmedabad, Visakhapatnam, and Chennai. Besides low anthropogenic emissions, long-range transport and prevailing meteorological conditions also played a significant role in governing the observed changes in aerosol loading and air pollutant concentration.

Flexibility improvement method of coal-fired thermal power plant based on the multi-scale utilization of steam turbine energy storage

In order to achieve the large-scale grid connection of renewable energy, flexibility of the power generation system operation needs to be improved. The coal-based power supply structure indicates that coal-fired generating units are gradually becoming the main force of power regulation in China. However, the coal-fired power unit load regulation capacity requires significant improvement. Based on the energy storage characteristics of the coal-fired power unit, a load regulation method based on the multi-scale energy storage utilization is proposed. The method is based on the combination of feedwater bypass throttling and feedwater heater extraction steam throttling. The coal-fired power unit mathematical model is established and verified against the field tests, and simulation relative error is approximately 7%. Based on the mechanism mathematical model, the load coordinated controlled model is obtained. Moreover, the load response time of feedwater bypass throttling method is nearly 125 s longer than that of high-pressure heater extraction steam throttling method, the load command is decomposed by multi-scales, and the load regulation method based on the feedwater bypass and extraction steam throttling is proposed. The simulation results indicate that the proposed method is superior to the conventional control method. Furthermore, it can effectively improve the unit load flexibility.

Developing an analytical model to predict the energy and exergy based performances of a coal-fired thermal power plant

In the present study, an analytical model has been developed to predict the effectiveness of the closed feedwater heaters based on the measured data available from a coal-fired thermal power plant. Invoking this model, a ‘Predictive Model’ has been developed to anticipate the energy and exergy-based behavior of the coal-fired power plants. In this model, all the components have been assumed to be installed, and hence they could not be changed. Based on this model, a numerical code has been developed to analyze an existing coal-fired power plant using Engineering Equation Solver software. Invoking this code, the impact of the operational conditions on the performance of the power plant is examined. The effects of superheater outlet pressure, superheater outlet temperature, and reheater inlet pressure upon energy and exergy-based parameters of the cycle have been examined. It has been observed that by increasing the superheater pressure by 100%, the net power delivered by the cycle increases more than 8%. While increasing the superheated steam temperature from 539.8 to 580 °C, the net power delivered by the cycle increases more than 6%. Further, by increasing the reheater pressure from 30 to 34 bar, the net power delivered by the cycle reduces 1.57%.

Research and development of high efficiency low emission combined cycle power plant arrangements

Coal-fired steam turbine thermal power plants produce a large part of electricity. These power plants usually have low efficiency and high carbon dioxide emission. An application of combined cycle power plants with coal gasification equipped with carbon capture and storage systems may increase the efficiency and decrease the harmful emission. This paper describes investigation of the oxidizer type in the integrated gasification combined cycle combustion chamber and its influence upon the energy and environmental performance. The integrated gasification combined cycle and oxy-fuel combustion technology allow the carbon dioxide capture and storage losses 58% smaller than the traditional air combustion one. The IGCC with air combustion without and with carbon dioxide capture and storage has 53.54 and 46.61% and with oxy-fuel combustion has 34.94 and 32.67% net efficiency. Together with this the CO2 emission drops down from 89.9 to 10.6 gm/kWh. The integrated coal gasification combined cycle with air oxidizer has the best net efficiency.

By-production of electricity and particulates: efficiency of Indian thermal power plants revisited

PurposeThis paper studies the efficiency of Indian coal-fired thermal power plants (CTPPs) in by-production of electricity and particulates also known as Suspended Particulate Matter (SPM).Design/methodology/approachA non-radial directional distance function is optimized using data envelopment analysis to enumerate the overall inefficiency of CTPPs and its components in recent times. Further, second-stage regression analysis is conducted to identify factors that affect the inefficiency of plants.FindingsThe low inefficiency score for electricity generation suggests that most CTPPs operate close to the good output frontier. A high degree of emissions inefficiency is a challenge for Indian CTPPs. Ever-rising coal use inefficiency is a hindrance to control SPM emissions. The second stage regression analysis concludes that factors like ownership and capacity utilization play vital roles in determining a plant’s inefficiency level. Privately owned CTPPs have performed better in terms of technical inefficiency and emission inefficiency than plants owned by Central and State governments.Originality/valueTo the best of the authors’ knowledge, this study is one of the few published works that benchmark the productive and environmental performance of Indian CTPPs.