Coal-fired Power Plants Research Articles

Cd/Pb behavior during combustion in a coal-fired power plant and their spatiotemporal impacts on soils: New insights from Cd/Pb isotopes

Coal power plants annually generate quantities of byproducts that release environmentally hazardous heavy metals like Cd and Pb. Understanding the behavior and spatiotemporal impacts on soils of these releases is crucial for pollution control. This study investigated the concentrations and isotope ratios of Cd/Pb in combustion byproducts, depositions and soils collected from a coal-fired power plant or its surrounding area. The pulverized fuel ash (PFA) and desulfurized gypsum (DG) exhibited heavier Cd isotopes with Δ114Cd values of 0.304‰ and 0.269‰, respectively, while bottom ash (BA) showed lighter Cd isotopes (Δ114CdBA-coal = –0.078‰), compared to feed coal. We proposed a two-stage condensation process that governs the distribution of Cd/Pb, including accumulation on PFA and DG within electrostatic precipitators and desulfurization unit, as well as condensation onto fine particles upon release from the stack. Emissions from combustion and large-scale transport make a significant contribution to deposition, while the dispersion of Cd/Pb in deposition is primarily influenced by the prevailing wind patterns. However, the distribution of Cd/Pb in soils not only exhibit predominant wind control but is also potentially influenced by the resuspension of long-term storage byproducts. The power plant significantly contributes to soil in the NW–N–NE directions, even at a considerable distance (66%–79%), demonstrating its pervasive impact on remote regions along these orientations. Additionally, based on the vertical behavior in the profile, we have identified that Cd tends to migrate downward through leaching, while variations in Pb respond to the historical progression of dust removal.

Features of the Mechanism of Gas-phase Ignition of Wood Biomass Particles

ABSTRACT Use of woody biomass instead of coal as fuel for thermal power plants (TPP) is considered a promising direction for reducing emissions of anthropogenic substances during the operation of coal-fired thermal power plants. But the process of replacing coal with wood in the thermal power industry is happening very slowly due to objective reasons. The main one is the deposition of particles that have not fully passed the pyrolysis stage (in this case, a layer of substance in a resinous state is retained in the wood particle) on heating surfaces (for example, superheaters) and a decrease in the efficiency of using the heat of combustion of fuel as a result of contamination of the heating surfaces. Therefore, when developing technologies for burning dispersed wood in the furnaces of boiler units, reliable experimental data are required on the characteristic times of ignition and combustion of woody biomass particles, taking into account the time of transition from local (focal) gas-phase ignition to the combustion of volatiles in the entire vicinity of the particle (tsf). The article presents the results of experimental studies of flame propagation processes in the small vicinity of a particle during the ignition period. The experiments made it possible to establish that the flame propagation velocity in the small vicinity of the particle significantly depends on the ambient temperature. It is shown that under conditions of low-temperature heating (air temperature Tg = 873 K), the propagation velocity of the combustion (flame) is minimal. An increase in Tg values (from 873 K to 1273 K) leads to a significant (4–5 times) increase in the time of complete flame coverage of the particle. According to the results of the experiments, two heating modes were identified: high-temperature and low-temperature with a conditional interface Tg = 873 K. At Tg = 873 K, the characteristic particle size of wood biomass has no significant effect on the characteristics and conditions of flame propagation in a small vicinity of the particle. An increase in the ambient temperature (up to 1273 K) leads to an increase in the influence of particle size on the characteristics and conditions of flame propagation. A hypothesis describing the process of flame propagation has been developed.

Feasibility of co-disposal of lignite and eucalyptus wood in coal-fired power plants: thermogravimetric characterization, typical gaseous pollutant emission characteristics, and economic analysis

ABSTRACT Energy issues are becoming increasingly prominent, and biomass blending in coal-fired power plants can improve combustion performance and reduce gaseous pollutant emissions, thereby improving economic efficiency. In this study, a thermogravimetric analyzer, a horizontal tube furnace, and an infrared flue gas analyzer were used to investigate the combustion behavior and gaseous pollutant emissions of the co-combustion of LC and EW. The results show that blending EW into LC cofiring can inhibit the release of volatile matter and promote the decomposition of fixed carbon and lignin simultaneously. The HHV of EW (15.88 MJ/kg) reaches 63.7% of LC’s (24.90 MJ/kg), indicating EW has a high energy utilization value. With increasing combustion temperature, the average value of CR S increased from 47.09% to 59.94%, and the average value of CR Cl increased from 26.15% to 52.15%, leading to a significant increase in SO2 and HCl emissions. The decrease in combustion temperature slightly promoted the release of N (CR N increased from 11.76% to 14.45%). The results of the economic analysis show that the cost of CaO and NH3·H2O used for removing gaseous pollutants decreased the most, and the economic efficiency increased the fastest to 14,000 RMB/day when the EW blending ratio increased from 10% to 20%.

Assessment of combustion residual leachate: Local treatment needs and critical mineral recovery

Combustion residual leachate from landfills and impoundments at coal-fired power plants represents a large volume of wastewater with variable treatment requirements prior to discharge. Treatment to meet these requirements can be costly, but simultaneously creates an opportunity to co-extract critical minerals. This work first characterizes the treatment needs by developing composite regional standards for 14 contaminants across the United States (U.S). We then assess data on leachate composition and present the total mineral mass and total market size that can be recovered during treatment. Magnesium has the largest total mineral mass and largest market size and can be extracted using commercially available technology. The average simulated value of this magnesium is $38 million from landfill leachate and $660 million from impoundment leachate. This would account for 9 % and 150 %, respectively, of U.S. annual consumption of magnesium.

Just transition out of coal-fired power: Policy lessons from Australia's automotive sector closure

Nearly three-quarters of Australia's electricity generation is coal-dependent with fossil fuel-led electricity contributing to over a third of Australia's CO2 emissions. Climate change imperatives are calling for permanent shifts to these patterns, leading to early closure announcements of several coal-fired power plants across the country. Although the pace and scale of the energy transition are unprecedented, the closure of large-scale industries is not uncommon. The most recent closure in Australia's industrial past that remains vivid in the nation's collective memory was the end of nearly 70 years of automotive manufacturing.Drawing on expert consultations, and applying just transitions and transition management thinking, this paper identifies four key insights from the auto sector closure experience. These offer compelling pointers to guide socio-economic transformations in frontline regions that are likely to face challenging, often deeply personal, impacts resulting from the closure of coal-fired power stations over the coming decades.

Effect of Cr on the high-temperature corrosion of dissimilar AISI 904L and Inconel 625 joints employed in the coal-fired thermal power plant tubes

ABSTRACT The hot corrosion behaviours of 5-mm-thick plates of dissimilar AISI 904L and Inconel 625 weldments produced by continuous current gas tungsten arc welding process using Ni-Cr-Mo-enriched filler wires (ERNiCrMo-4 and ERNiCrCoMo-1) were investigated. Optical microscopy was used to examine the microstructure of these weldments. The corrosion performance of the weldments and base metals was determined in the mixture of K2SO4 + 60% NaCl molten salt (MS) and air oxidation conditions at 700°C for 50 cycles. The thermogravimetric plots derived the corrosion kinetics of the weldments. The microstructure and the elemental analysis of the scales formed on the corroded samples were evaluated by scanning electron microscopy and energy-dispersive spectroscopy. The phases developed on the oxide layers during the corrosion were analysed using X-ray diffraction. The fusion zones of ERNiCrCoMo-1 weldment and AISI 904L base metal were vulnerable to degradation in the MS environment, causing severe cracks and spallation compared to ERNiCrCoMo-1 weldment.

The Effect of Acid Treatment Time, Particle Size, and Synthesis Method on the Physical and Mechanical Properties of Dental Materials Produced from Flue Gas Desulfurization (FGD) Gypsum

FGD gypsum, a byproduct of coal-fired power plants, is readily available and relatively inexpensive, which makes it an ideal material for a variety of applications. This study considered the use of FGD gypsum as a substitute for natural gypsum in dental materials. The goal of this research was to investigate how acid treatment time, particle size, and the synthesis method impact the physical and mechanical properties of dental materials to be used in a dental study model for training in dental sciences, and for casting a gypsum model after the removal of the impression material from the patient's mouth. The study used various sulfuric acid treatment times (15, 30, and 60 min), particle sizes (less than 0.1 mm, 0.1-0.35 mm, and 0.4-0.45 mm), and synthesis methods (Method A for dental plaster and Method B for dental stone). From the results, an acid treatment time of 15 min was sufficient for removing impurities from the FGD gypsum while enhancing the compressive strength. The smaller particles provided higher compressive strength than the larger particles. FGD gypsum became lighter in color when treated with sulfuric acid, and the crystal structure had a rough and porous surface. The synthesis methods had a significant influence on the physical properties of dental gypsum. The increased alpha calcium sulfate hemihydrate (α-HH) phase content resulted in improved compressive strength. The gypsum synthesized using Method B exhibited the highest compressive strength due to the presence of the α-HH phase of 65.9%. While gypsum synthesized using Method A contained a α-HH phase of 58.9%. For further study, once the suitable conditions for synthesizing gypsum that meet the compressive strength requirements of the ISO standard for dental materials are achieved, there will be ongoing research and development to improve various properties. Additionally, practical applications will be considered, such as using it in conjunction with modern techniques such as 3D printing instead of traditional die-casting methods.

Parameter analysis on SO3 measurement in coal-fired flue gas with controlled condensation method

ABSTRACT The accurate, repeatable, and verifiable measurement of SO3/H2SO4 is significant to the reliability operation of coal-fired power plants, as well as environment protection and human health. Although the amount of SO3 in flue gas is very small, and its chemical property is extremely active, the measurement of SO3/H2SO4 is difficult and problematic. The measurement errors of controlled condensation method for SO3/H2SO4 in flue gas were evaluated with a sampling system based on dilute sulfuric acid heating method. In order to improve the test accuracy of this method, the effects of water bath temperature, flue gas sampling flow rate, and spiral condensing tube structure parameters (inner diameter and length of spiral condensing tube) on the recovery efficiency of SO3/H2SO4 were investigated. The results indicate that the recovery efficiency fluctuates in the range between 84.1% and 91.6%, with the water bath temperature increasing from 40°C to 90°C. As the flue gas sampling flow rate increases from .5 L/min to 4 L/min, the recovery efficiency of SO3/H2SO4 shows a gradual tendency of increasing, and the recovery efficiency can be high up to 98.4%. When the inner diameter of the spiral condensing tube increases from 3 mm to 10 mm, the recovery efficiency of SO3/H2SO4 decreases gradually. The recovery efficiency of SO3/H2SO4 increases gradually with the spiral condensing tube length increasing from 900 mm to 2000 mm.

Thermal energy storage integration for increased flexibility of a power plant with post-combustion CO2 capture

Flexible operation of thermal power plants will become increasingly relevant in the coming years. This work evaluates the effect of integrating a steam accumulator into a 598 MW supercritical coal-fired power plant with moving bed temperature-swing adsorption CO2 capture. Charging the accumulator with reheat steam from the turbine train can reduce the net power output by up to 1.4 % (8.2 MW) for around 200 min. Small charging flow rates are recommended to maximize the final pressure of the accumulator. Covering the sorbent regeneration duty and meeting the demand of two feedwater heaters were considered as alternatives for discharging of the accumulator. Thermal storage discharging was found to give relative power plant load increases between 1.7 and 11.2 % (10.2–66.9 MW) for up to 37.5 min, which exceeds the requirement for primary reserve. Increases in the electrical energy output of 10.5–11 MWh were achieved. The flexibility modes studied in this work are compatible with high CO2 recovery rates.

Coal Control and Carbon Reduction Path in Henan Province's Power Industry Under the Carbon Peak and Neutralization Target: A Medium- and Long-term Study

Achieving peak carbon dioxide emissions and accelerating decarbonization progress in the power industry is of paramount significance to Henan Province's objective of achieving carbon peak and neutrality. In this study, the Carbon Emission-Energy Integrated Model (iCEM) was employed to conduct scenario studies on the coal reduction and carbon reduction paths under the "dual-carbon" goal of Henan's power industry. The results indicated that, by considering measures such as optimizing the power source structure and technological progress, Henan Province's power industry carbon emissions will reach their peak between 2028-2033, with coal consumption in the power industry continuing to grow during the "14th Five-Year Plan" period. With a peak range between 2027-2031, the peak value increased by 1881, 1592, and 11.48 million tce, respectively, compared with that in 2020. To control coal in Henan Province under the constraint of carbon peak goals, it is proposed to develop clean energy sources such as wind and solar power, use more low-carbon or zero-carbon heat sources, increase the proportion of external electricity supply, and enhance energy-saving transformation in coal-fired power plants. Accelerating the elimination of backward units and energy-saving transformation of existing units, accelerating non-fossil energy development, advanced planning for external electricity supply, improving market mechanisms for the exit of coal-fired power plants and peak regulation, increasing system flexibility, and accelerating external policies to ensure clean energy security are effective paths for controlling coal and reducing carbon emissions in Henan's power industry. Additionally, inland nuclear power layout is one of the crucial paths to alleviate coal control pressure in Henan Province and achieve "dual-carbon" goals during the carbon-neutral stage. Therefore, it is imperative to conduct research on demonstrations in advance. Henan Province is highly dependent on energy from other provinces, and the power supply and demand situation in Henan Province will become increasingly tense in the future. It is necessary to support Henan Province from the State Grid and coordinate the construction of inter-provincial and inter-regional power transmission channels.

Thermal energy storage capacity configuration and energy distribution scheme for a 1000MWe S–CO2 coal-fired power plant to realize high-efficiency full-load adjustability

The flexibility transformation of coal-fired power plants (CFPP) is of significant importance for the new power system primarily based on new energy sources. Coupling thermal energy storage (TES) technology is one effective approach to enhance the load-following capability of CFPPs. In this study, the S–CO2 CFPP coupled with TES technology is taken as the research object. An integrated dynamic energy analysis model, from components to the entire system, is established for variable working conditions. A comprehensive comparison is made among different TES methods, including flue gas TES, CO2 TES and electrical heating TES, in terms of system's minimum output power, thermal efficiency, energy round-trip efficiency and other off-design performance indicators. Furthermore, through hierarchical integrated configuration of the three thermal energy storage methods, efficient load regulation from 0% to 100% is achieved for the S–CO2 CFPP. The results indicate that, to achieve efficient load regulation from 0% to 100% for a 1000 MWe S–CO2 CFPP, the priority configuration for thermal energy storage is CO2 TES, followed by flue gas TES and electrical heating TES, with powers of 285.17 MWth, 342.80 MWth, and 329.95 MWth, respectively. The overall heat storage/release ratio is 3.43:1 and the energy storage round-trip efficiency is 73.58%. Compared to using only electrical heating TES, the addition of 142.34 MWth of TES improves the energy round-trip efficiency by 11 percentage points.

Coal-Fired Power Plants Using Ammonia for Flexibility Enhancement under Carbon Control Strategies: Status, Development, and Perspectives

Coal-Fired Power Plants Using Ammonia for Flexibility Enhancement under Carbon Control Strategies: Status, Development, and Perspectives

Finite element modelling of ultrasonic backscattered waves for improving creep void detection

ABSTRACT Ultra-supercritical coal-fired power plants in Japan and globally experience creep damage in the welded parts of their high-chromium steel assets. As the creep damage advances, voids develop at depth by preference and become dense and cause accidents. The voids cannot be detected using existing non-destructive methods, causing the unreasonable and uneconomic management of plants. To establish a non-destructive examination method that can be used for practical and economic maintenance, a detection method for dense creep voids using ultrasonic backscattered waves is proposed herein. The creep-damaged structures are modelled using a transducer and the transmission and reception characteristics are discussed. These characteristics are considered using the finite element method, as they cannot be measured through normal experiments. The results show that without a focusing process at the time of reception, changes in the amplitude of backscattered waves cannot be confirmed; thus, the contribution of transmission focus to creep void detection is limited. Conversely, it is confirmed that when the received backscattered waves in the direction normal to the transducer are integrated and the phase matching is reflected, the amplitude of the scattered waves increases with creep void density. The reception focus considerably contributes towards dense creep void detection.

A generalized data assimilation architecture of digital twin for complex process industrial systems

As one of the critical cores of digital twin (DT), data assimilation (DA) can maintain consistency and synchronization between DT and physical system. Kalman filtering is a common DA method, but its estimation performance is deteriorated by factors such as model inaccuracy and time-varying noise covariance in practical applications. The errors caused by these multiple uncertainties are all coupled to the measurements, which augments the difficulty for DT to obtain physical system information. In order to tackle the DA problem with multiple uncertainties, this paper proposes a generalized DA architecture for DT in sophisticated process industry. First, by combining Stein variational gradient descent and nonlinear Bayesian filtering paradigm, a recursive estimation framework is established, which has higher accuracy in estimating the noise covariance compared to traditional methods. Second, to effectively deal with model inaccuracy by using filtering residuals containing time-varying noise, we propose a neural network and modified wavelet-based model error compensation (NNMW-MEC) block. Based on the modified wavelet technique, the filtering residual denoising built in NNMW-MEC can better cope with time-varying noise compared to existing wavelets, and extract the low-frequency signal involving model error information from noisy residual smoothly. In addition, because of the neural network-based state-compensation subblock, NNMW-MEC has more outstanding ability in compensating the state deviations with large changing range. Finally, we take the boiler system in a coal-fired power plant as an example to verify the effectiveness of our architecture. Experimental results show that the DA architecture proposed in this paper can improve the estimation performance of DT under inaccurate models and uncertain noise statistics.

Joint Modeling and Operational Optimization of a Reverse Osmosis-Mechanical Vapor Recompression System for Coal-Fired Power Plant Wastewater.

The operation of coal-fired power plants generates a large amount of wastewater. With the issuance of increasingly strict drainage standards, the cost of wastewater treatment is increasing, and the need to reduce the cost of wastewater treatment is becoming increasingly urgent. Thus, based on the principles of reverse osmosis (RO) and mechanical vapor recompression (MVR) in wastewater treatment, the operational optimization of an RO-MVR joint system was studied in this work with the consideration of reducing the operating costs of wastewater treatment under given operational conditions. Firstly, based on the basic principles of RO and MVR, corresponding mechanism models were established and their accuracy was verified. Then, an economic model of the RO-MVR joint system was established, with the goal of minimizing the water production unit price and daily operating costs of the joint system for optimization analysis. Finally, we analyzed the cost and water production performance of the RO-MVR joint system before and after optimization under different operating conditions. The results show that this optimization based on the RO-MVR joint system will reduce the unit price of water production to 3.16 CNY/m3, with the daily operating costs being decreased by 22% compared to before optimization. This result helps to reduce the cost of zero-discharge wastewater treatment in coal-fired power plants.

Health risks of exposure to air pollution in areas where coal-fired power plants are located: protocol for a scoping review

IntroductionCoal-fired power plants are major sources of air pollution which impact human health. Coal combustion byproducts released into the air include particulate matter, nitrogen oxides and sulphur dioxide. Exposure to...

The evolutionary analysis of investment in CCS-EOR under dual carbon target—From the perspective of multi-agent involvement

Carbon capture and storage with enhanced oil recovery (CCS-EOR) technology plays a crucial role in achieving dual carbon targets in China. And the rapid diffusion of technology requires collaboration among various stakeholders involved in industrial chain of CCS-EOR project and then it will cause conflict of interest among the participants. In order to solve the problem existing in CCS-EOR promotion and propel the rapid deployment of low-carbon technology in China, the paper constructs a tripartite evolutionary game model by incorporating the strategic choices of coal-fired power plants, oilfield enterprises and governments into the framework, explores the respective dynamic evolutionary path of three parties and analyzes the impact of each parameter change on the system evolution results Through the numerical simulation, the paper identifies the optimal evolutionary path to spur the application of CCS-EOR and determine their strategy choices of three involved subjects in the game framework. Based on the sensitivity analysis, results are given as follows: (1) The government's clean electricity subsidy and carbon utilization subsidy have pushed the timing of CCS retrofitting significantly forward, but the initial investment subsidy has little impact on it; (2) Under the cooperation mode of coal-fired power plants and oilfield enterprises, the optimal cost-sharing ratio of the initial investment for coal-fired power plants is about 0.4 to promote both sides to reach cooperation faster. Once it exceeds 0.4, the probability of cooperation between them will be significantly reduced; (3) The carbon tax policy effectively propels the development of CCS-EOR technology. When the carbon tax rises from 30 CNY/t to 120CNY/t, power plants will conduct CCS retrofitting investment two years in advance.

Investigation of Ammonia Co-firing Effects on Combustion Equipment Performance in an Existing PLN 660 MW Coal-fired Power Plant

Investigation of Ammonia Co-firing Effects on Combustion Equipment Performance in an Existing PLN 660 MW Coal-fired Power Plant

The Impact of Russia’s Invasion of Ukraine on Germany’s Energy Choice Attitudes among Residents in German States with Nuclear Power Plants in Commission or Decommissioned

This paper examines the impact of Russia’s invasion of Ukraine on the Germany public’s energy choices. Along with much of Europe, Germany was hit by Russia reducing and then cutting its gas supplies. Although alternative sources have been found, this exposes the vulnerability of Germany’s energy market to outside control. An online survey of 600 German consumers was conducted in August 2022. The results suggest that 70% of participants were concerned about the shortage of oil and natural gas supply after Russia’s invasion of Ukraine, and 60% were concerned about the shortage of electricity supply. The invasion led many participants to support maximizing the use of existing power plants, including nuclear and coal-fired power plants, as an alternative to dependency on Russian supplies. There was an increase in people supporting the expanded use of renewable energy as a solution to the crisis. States with nuclear power plants were seen as needing to reduce and decarbonize their natural gas and coal-fired power generation while advancing their energy mix. The results suggest that the Energiewende approach and objectives have broad public support.

Comparative Analysis of Heavy Metal Exposure Concentrations and Volatile Organic Compound Metabolites among Residents in the Affected Area According to Residential Distance from a Coal-fired Power Plant

Comparative Analysis of Heavy Metal Exposure Concentrations and Volatile Organic Compound Metabolites among Residents in the Affected Area According to Residential Distance from a Coal-fired Power Plant