Coal-fired Power Plants In China Research Articles

The distribution and enrichment characteristics of rare earth elements between coals and coal ashes from four coal-fired power plants.

Coal and coal ash (slag and fly ash) have emerged as important potential sources for rare earth elements (REY). The distribution and enrichment of REY during coal combustion from coal-fired power plants are of great significance for the recovery of REY. In this study, the concentration of REY in coal and coal ash from four coal-fired power plants in China was determined using microwave digestion-inductively coupled plasma mass spectrometry. The distribution and enrichment characteristics of REY in coal and coal ash were studied. The coal ash contains 310-683 μg g-1 of REY, and the proportion of critical REY was greater than 30%, which is higher than the extraction concentration (300 μg g-1) recommended by the United States Department of Energy, indicating significant REY recovery potential. The concentration of REY in coal was positively correlated with ash yield, which could be explained by the fact that REY are mainly distributed in minerals. Coal and coal ash show similar REY distribution patterns, indicating that REY were not fractionated during the coal combustion. In addition, the enrichment coefficient of REY in fly ash was greater than that in slag, which revealed that REY were mainly enriched in fly ash. Therefore, the REY in fly ash has more recycling potential.

Removal and emission characteristics of hazardous trace elements in total and graded particulate matters: A case study of a typical ultra-low emission coal-fired power plant

Particulate matters (PMs) and hazardous trace elements (HTEs) emitted from coal-fired power plants (CFPPs) have raised serious environmental and human issues. Herein, total PMs and graded PMs including PM<1, PM1–2.5 and PM2.5–10 at the inlet/outlet of air pollution control devices (APCDs) were collected from a representative ultra-low emission (ULE) CFPP in China. The removal efficiencies of total PMs by selective catalytic reduction (SCR), electrostatic precipitator (ESP), wet flue gas desulfurization (WFGD) and wet electrostatic precipitator (WESP) were 0.40 %, 99.9 %, 38.1 % and 85.3 %, respectively. PM2.5–10 was robustly removed by WFGD, while PM<1 and PM1–2.5 were readily removed by WESP. The removal efficiencies of As, Cd, Cr and Pb in total PMs by APCDs followed an order: ESP > WESP > WFGD > SCR. SCR significantly decreased Se concentration by 42.8 %, contrasting to the removal of As, Cd, Cr and Pb (10.8–20.8 %). As, Cd, Cr, Pb and Se concentrations in graded PMs at the outlets of ESP, WFGD and WESP decreased with particle size increasing. All As, Cd, Cr, and Pb contents in PM<1, PM1–2.5 and PM2.5–10 at WFGD outlet increased, surpassing their analogues at ESP and WESP outlets. However, the concentration of Se declined in PM<1 at WFGD outlet. The atmospheric emission factors (EFs) of As, Cd, Cr, Pb and Se in the studied ULE CFPP were respectively 7.32, 1.27, 6.05, 122.5 and 6.42 mg/t, in line with Monte Carlo simulations. This study would not only provide a basis for emission control of PMs and HTEs in CFPPs, but also promote the improvement of respective environmental policy.

The influence of air pollution control devices on gas organic pollutants emission from coal-fired power plants based on LCA

Air pollutants (e.g., NOx, SO2) emitted from coal-fired power plants in China have been effectively controlled by Air Pollution Control Devices (APCDs) since 1996. However, the gas organic pollutants (typically Volatile Organic Compounds (VOCs) and Polycyclic Aromatic Hydrocarbons (PAHs)) have been overlooked for a long time. In this study, based on the life cycle assessment method, the effect of APCDs (mainly Selective Catalytic Removal (SCR), Electrostatic Precipitator (ESP), Wet Flue Gas Desulfurization (WFGD), and Wet Electrostatic Precipitator (WESP)) on gas organic pollutants (without methane) from three typical coal-fired power plants in China has been evaluated in terms of direct emission removal and indirect emissions. Detecting the gas organic pollutants concentrations at the inlet and outlet of APCDs in these three cases, it is found that the total direct emission removal efficiency is up to more than 71.97%, with SCR’s contribution being the highest. However, the manufacture and equipping of APCDs will lead to indirect emission of gas organic pollutants. The result shows that the SCR system is also the main process that induces indirect emissions of gas organic pollutants, associated with the utilization of liquid ammonia and catalyst. Compared to the direct emission of gas organic pollutants, indirect gas organic pollutants emissions can not be ignored. The calculation of net emission removal and the degree of co-effects shows that APCDs can reduce gas organic pollutants, which results in reducing the photochemical ozone creation potential of 1.81E-06~5.93E-06kg(Ethene eq.)/MW·h and human toxicity potential of 2.51E-03~8.06E-03kg (DCB eq.)/MW·h.

Potential of China's national policies on reducing carbon emissions from coal-fired power plants in the period of the 14th Five-Year Plan

Coal-fired power is one of the largest contributors to China's carbon emissions. To promote its national low-carbon transition ambitions, the Chinese government has issued a series of policies to reduce emissions from coal-fired power plants (CFPP) during its 14th Five-Year Plan (2021-2025). This study mainly focuses on the mitigation potential of related national policies, using global optimization methods with double constraints on different policy implementation extents and power supply security under different scheduled views of national new energy developments. Thereby, 81 scenarios are set, and policy simulations till 2025 are conducted, achieving emission reductions ranging from 0.39 Gt to 1.04 Gt across scenarios. Specifically, if all policies are implemented as planned, they can bring significant changes, 0.64 Gt CO2 cumulative reduction and 25 Mt/GWh emitting efficiency improvement. But the simulated emission-changing trend shows that they may not be sufficient for the nation's target of peaking emissions before 2030, while results in higher-extent scenarios indicate that stronger implementation is required for this target. More relevant recommendations are also provided for subsequent sustainability policies on CFPPs in China.

Investment decisions on carbon capture utilization and storage retrofit of Chinese coal-fired power plants based on real option and source-sink matching models

Carbon Capture Utilization and Storage (CCUS) is the only technological option for decarbonizing existing coal-fired power plants (CFPPs) deeply, yet its current scale is far from the level required to meet global climate goals. How carbon price can facilitate CCUS decarbonization of CFPPs in China is a great concern. This study couples a CCUS source-sink matching optimization model covering onshore and offshore geological storages with a trinomial-tree real options model, by which the Chinese critical carbon prices for CCUS investment at different emission reduction potentials are quantified. The results show that when the carbon price reaches 100, 200, and 400 CNY/t, then 24, 28, and 314 GW of CFPPs will enable to invest in CCUS immediately, achieving cumulative 1.8, 2.1, and 24.3 GtCO2 emission reductions over their remaining lifetime. To meet the global warming 2 °C target constraint on China's power sector, the carbon price need to reach 370 CNY/t.

Evolution behavior of mineral structure and trace elements in feed coals from six coal-fired power plants in China.

Chemical composition, surface morphology characteristics, and mineralogical characteristics of feed coals from six power plants were studied in this paper, as well as alteration behavior of mineral phase, functional groups, and trace elements during combustion. The apparent morphology of feed coals is different in compactness and order, while sharing a similar lamellar shape. Quartz, kaolinite, calcite, and illite are the main minerals in feed coals. There are obvious differences in the calorific value and temperature range in volatiles stages or coke combustion stages for feed coals. Peak positions for the main functional groups in feed coals are similar. After burning at 800 ℃, most organic functional groups in feed coals were lost in products, but the group of -CH2 on the side chain skeleton of n-alkane and the aromatic hydrocarbon bond (Ar-H) still existed in the ash, and the vibration of Si-O-Si bond and Al-OH bond in inorganic functional groups was strengthened. During combustion, Pb and Cr in feed coals will be accumulated in the mineral residues, unburned carbon, and residual ferromanganese minerals, along with the loss of organic matter and sulfide or the decomposition of carbonate. Pb and Cr are more easily adsorbed by the fine-graded coal combustion products. Occasionally, the abnormal phenomenon occurred ina medium-graded ash butwiththemaximum adsorptionof Pb and Cr, which is mainly caused by the collision and agglomeration of the combustion products, or the adsorption capacity of different mineral components. The effects of diameter, coal species and feed coal on the forms of Pb and Cr in combustion products were also analyzed in this study. The study has some guiding significance for understanding the behavior track and alteration mechanism of Pb and Cr during coal combustion.

Oxidative Potential of Metal-Containing Nanoparticles in Coal Fly Ash Generated from Coal-Fired Power Plants in China

Oxidative Potential of Metal-Containing Nanoparticles in Coal Fly Ash Generated from Coal-Fired Power Plants in China

Hyperspectral imaging technique supports dynamic emission inventory of coal-fired power plants in China

Hyperspectral imaging technique supports dynamic emission inventory of coal-fired power plants in China

Marginal CO2 and SO2 Abatement Costs and Determinants of Coal-Fired Power Plants in China: Considering a Two-Stage Production System with Different Emission Reduction Approaches

Marginal abatement cost (MAC) plays an essential role in pricing pollutants and guiding environmental policies. Considering the heavy polluting nature of China’s coal power industry, this paper aims at providing companies and policymakers with more comprehensive information on the cost of abatement by estimating the MACs of CO2 and SO2 for coal-fired power plants (CFPPs) in China. This study contributes to the literature by considering an interconnected two-stage production system to investigate. The estimation framework is advanced in combining the electricity production and pollution abatement process of CFPPs into a convex quantile regression (CQR) model. The results show that the averages of MAC for CO2 and SO2 are estimated to be 367.56 Yuan/ton and 662.30 Yuan/ton, respectively, indicating that the reduction of such emissions is still costly. The heterogeneous analysis then indicates that large CFPPs, central-government-owned power plants (CGOPPs), and low-regulated CFPPs tend to possess lower MACs for CO2. Regarding SO2, large and medium-sized power plants show significantly larger MACs than small plants. In addition, the MACs of SO2 for CGOPPs and high-regulated CFPPs are more concentrated at high levels. In the second part, the Tobit regression analysis was used to discuss the determinants of MACs for CO2 and SO2. Factors like carbon emission intensity, load, and operating hours can notably decrease MACs for CO2, while MACs for SO2 tend to be positively affected by the total abatement cost and the abatement rate of the FGD equipment. In addition, the MACs for the large CFPPs, CGOPPs, and high-regulated CFPPs are more likely to be affected by the selected influence factors. Based on these results, we conclude with some policy recommendations.

Research on CCUS business model and policy incentives for coal-fired power plants in China

Carbon capture, utilization and storage (CCUS) is currently the most potential cutting-edge emission reduction technology in China to achieve the vision of carbon neutrality. The industrialization of CCUS faces multiple challenges such as high cost, technical security and public acceptance, but the lack of mature business model and corresponding incentive policies is the main restrictive factor affecting the industrialization of CCUS technology. Therefore, exploring a feasible CCUS business model and formulating relevant incentive policies are of great significance for promoting the commercial deployment of CCUS and achieving the national carbon neutrality goal. Focusing on coal-fired power plants, this paper uses the system dynamics method to compare and analyze two different CCUS business models from the perspectives of economy, technical feasibility and emission reduction benefits, and evaluate the system operation effects under different incentive policy scenarios. The research results show that the vertical integration model is the most potential CCUS business model in China at present, and different incentive policies will cause different changes in the CCUS system. Based on the research conclusions, this paper puts forward suggestions such as formulating differentiated power generation quota subsidy policies and actively developing the carbon emission trading market.

Developed compositional source profile and estimated emissions of condensable particulate matter from coal-fired power plants: A case study of Yantai, China

The emission and environmental impact of condensable particulate matter (CPM) from coal-fired power plants (CFPPs) are of increasing concern worldwide. Many studies on the characteristics of CPM emission have been conducted in China, but its source profile remains unclear, and its emission inventory remains high uncertainty. In this work, the latest measurements reported in the latest 33 studies for CPM inorganic and organic species emitted from CFPPs in China were summarized, and then a compositional source profile of CPM for CFPPs was developed for the first time in China, which involved 10 inorganic species and 71 organic species. In addition, the CPM emission inventory of CFPPs in Yantai of China was developed based on surveyed activity data, continuous emission monitoring system (CEMS), and the latest measurement data. The results show that: (1) Inorganic species accounted for 77.64 % of CPM emitted from CFPPs in Yantai, among which SO42− had the highest content, accounting for 23.74 % of CPM, followed by Cl−, accounting for 11.95 %; (2) Organic matter accounted for 22.36 % of CPM, among which alkanes accounted for the largest proportion of organic fraction (72.7 %); (3) Emission concentration method (EC) and CEMS-based emission ratio method (ERFPM,CEMS) were recommended to estimate CPM emissions for CFPPs; (4) The estimated CPM emission inventories of Yantai CFPPs in 2020 by the EC method and the ERFPM,CEMS method were 1231 tons and 929 tons, respectively, with uncertainties of −34 % ∼ 33 % and −27 % ∼ 57 %, respectively; (5) CPM emissions were mainly distributed in the northern coastal areas of Yantai. This developed CPM source profile and emission inventory can provide basic data for assessing the impacts of CPM on air quality and health. In addition, this study can provide an important methodology for developing CPM emission inventories and CPM emission source profiles for stationary combustion sources in other regions.

Analysis on Feasibility of Applying Low-Temperature Emission to Coal-fired Power Plant in Cold Weather

After the ultra-low emission(ULE) transformation, the emissions of ULE coal-fired power plants in China have been reduced greatly. However, considering the total amount of emissions, coal-fired power plants are still among the largest sources. And there may still have great potential in the removal of colored plume and some unconventional pollutants such as condensable particles matter (CPM) and sulfur trioxide (sulfuric acid mist). Though in cold days, hazes occur frequently. Besides, low-temperature condensation is conducive to the condensation and removal of vapor, CPM and sulfur trioxide in the flue gas. In this paper, a new method of low-temperature flue gas emission is proposed for coal-fired power plants in severe cold areas. The flue gas is cooled by ambient air, and discharged without reheating, and remarkable effects can be achieved in removing the pollutants. The technical feasibility and environmental compliance of applying this method to a power plant in cold weather have been analyzed. The results show that low-temperature emission of flue gas for coal-fired power plants in winter is effective in water-saving, emission reduction of pollutants and elimination of wet plume.

Speciation, bioaccessibility and human health risk assessment of chromium in solid wastes from an ultra-low emission coal-fired power plant, China

Chromium (Cr) in solid wastes from ultra-low emission (ULE) coal-fired power plants (CFPPs) could engender adverse effects on environment and human health. Hence, solid waste samples containing bottom ash, fly ash, gypsum and sludge were collected from a typical ULE CFPP in China to study the distribution, speciation, bioaccessibility and human health risk of Cr. The results showed that Cr was depleted in gypsum, whereas significantly enriched in bottom ash, fly ash and sludge comparing with feed coal. The ratios of Cr(VI) to total Cr in solid wastes were relatively low, but the increase of flow fractions in Cr chemical binding forms implied the deterioration of environmental stability. Based on the in vitro simulated digestion methods of solubility bioavailability research consortium (SBRC) and physiologically based extraction test (PBET), the bioaccessibility of Cr in the gastric and intestinal phases reached the highest values in either gypsum or sludge. After incorporating bioaccessibility in human health risk assessment, the carcinogenic risk (CR) within acceptable limits of Cr in solid wastes to adults and children was concluded, with the non-carcinogenic hazard quotient (HQ) was all within the safety threshold. The Monte Carlo model was applied to evaluate the uncertainty analysis of human health risk assessment at 5% and 95% confidence interval, and the fitting results were consistent with the calculation results of the carcinogenic and non-carcinogenic risk for adults and children. This study is expected to provide insights for the integration of bioaccessibility into the health risk assessment of Cr in solid wastes from ULE CFPPs, thus is conducive to the disposal of solid wastes and human health protection.

Vast emission of Fe- and Ti-containing nanoparticles from representative coal-fired power plants in China and environmental implications

Coal combustion is considered an important source of atmospheric nanoparticles (NPs). However, the underlying information on the emission of NPs from coal-fired power plants (CFPPs) is still lacking. Along these lines, in this study, coal fly ashes (CFAs) were collected from different multi-stage particulate emission control devices (PECDs) in three representative CFPPs in China. The particle size and particle number concentration (PNC) of typical metal-containing NPs (Fe- and Ti-containing NPs) were analyzed by using the single-particle inductively coupled plasma mass (SP-ICP-MS) technology. By increasing the stage of PECDs, the mean particle sizes of NPs gradually declined and the PNCs of Fe- and Ti-containing NPs increased significantly. Specifically, the PNC of final-stage CFA was 3 - 8 times that of the first-stage CFA. A comparison of the electrostatic precipitators (ESPs), fabric filters (FFs), and electrostatic-fabric-integrated precipitators (EFIPs) showed that the state-of-the-art EFIPs exhibited a relatively good NP-removal efficiency with the highest PNCs. In addition, NP hourly emissions in all coal combustion by-products (CCPs) were further calculated in a typical CFPP. The total emissions of Fe- and Ti-containing NPs in all CCPs were 1.87 × 1018 and 1.57 × 1018 particles/h, respectively. NPs were mainly enriched in CFA trapped by PECDs (80% of total emissions). Although the mass of the CFA that escaped through the stack was extremely low, it contained the highest PNCs of Fe- and Ti-containing NPs of all CCPs, accounting for 3.41% and 1.67% of the corresponding total NP emissions. These NPs may also coexist with various toxic metals, such as Zn and Pb, and be released directly into the atmosphere, where they pose a potential risk to human health.

Daily Emission Patterns of Coal-Fired Power Plants in China Based on Multisource Data Fusion.

Daily emission estimates are essential for tracking the dynamic changes in emission sources. In this work, we estimate daily emissions of coal-fired power plants in China during 2017-2020 by combining information from the unit-based China coal-fired Power plant Emissions Database (CPED) and real-time measurements from continuous emission monitoring systems (CEMS). We develop a step-by-step method to screen outliers and impute missing values for data from CEMS. Then, plant-level daily profiles of flue gas volume and emissions obtained from CEMS are coupled with annual emissions from CPED to derive daily emissions. Reasonable agreement is found between emission variations and available statistics (i.e., monthly power generation and daily coal consumption). Daily power emissions are in the range of 6267-12,994, 0.4-1.3, 6.5-12.0, and 2.5-6.8 Gg for CO2, PM2.5, NO x , and SO2, respectively, with high emissions in winter and summer caused by heating and cooling demand. Our estimates can capture sudden decreases (e.g., those associated with COVID-19 lockdowns and short-term emission controls) or increases (e.g., those related to a drought) in daily power emissions during typical socioeconomic events. We also find that weekly patterns from CEMS exhibit no obvious weekend effect compared to those in previous studies. The daily power emissions will help to improve chemical transport modeling and facilitate policy formulation.

Comparative analysis of the marginal abatement cost modeling for coal-fired power plants in China

Emissions trading system (ETS) is an effective approach to achieve China's “double carbon” targets. An accurate measurement of carbon MAC (marginal abatement cost) serves as the basic evidence for the stability of ETS and market validity. This paper constructs a comprehensive analytical framework, including four parametric and two non-parametric methods, to analyze the efficiency and carbon MAC of 92 large coal-fired power plants in China. Results show that the average technical efficiency and shadow price were 0.92 and 13.63 RMB/ton, respectively. As verified by Monte Carlo simulations, each method has its cons and pros, while the MAC calculated by the parametric stochastic frontier analysis (SFA) is the closest to the real carbon market price. Additional analyses show that the MAC is positively related with plant scale and negatively related to the provincial carbon intensity targets. This result suggests power plants' technological progress and the asymmetric government subsidies.

Technology development and cost analysis of multiple pollutant abatement for ultra-low emission coal-fired power plants in China

The implementation of ultra-low emission (ULE) limits (SO2: 35 mg/m3, NOx: 50 mg/m3, PM: 10 mg/m3) promoted the development of flue gas treatment technologies in China. Pollutant control technology development for Chinese coal-fired power plants was summarized and an analysis of the applicability and cost of pollutant control technologies was conducted. Detailed data were collected from 30 ultra-low emission coal-fired units across China. Based on a cost analysis model, the average unit power generation incremental costs were 0.0144 and 0.0095 CNY/(kW·hr) for SO2 and NOx control technologies, respectively. The unit power generation incremental cost of twin spray tower technology was 7.2% higher than that of dual-loop spray tower technology. The effect of key parameters on operating cost was analyzed. The unit power generation incremental cost increased because of increments in the electricity price for SO2 control technology and the price of the reductant in NOx control technology. With high sulfur content or NOx concentration, the unit power generation incremental cost caused by pollutant control increased, whereas the unit pollutant abatement cost decreased. However, the annual operating hours or load increased, thereby leading to a decline in unit power generation incremental cost and unit pollutant abatement cost.

Spatial autocorrelation analysis of the environmental efficiency of coal-fired power plants in China

Spatial autocorrelation analysis of the environmental efficiency of coal-fired power plants in China

Study on the condensable particulate matter removal characteristics of air pollution control devices in a Chinese ultra-low emission coal-fired generating unit

Condensable particulate matter (CPM) belongs to PM25. In addition, it is one of PM2.5 main contributors. But CPM emissions are often overlooked in coal-fired power plants. As a result, this paper studies the removal characteristics of (CPM) from air pollution control devices (APCDs) in a Chinese ultra-low emission coal-fired generating unit. The quality and content of flue gas particles, including CPM and filterable particulate matter (FPM), were measured at four points: the selective catalytic reduction (SCR) input, air preheater (APH) inlet, electric precipitator (ESP) outlet, and wet flue gas desulphurization (WFGD) outlet. The removal characteristics of each APCD were studied. Within the scope of this study, it is found that: ® CPM emission concentration accounts for 94.9% of total particle emission concentration, and is higher than the ultra-low particulate matter outflow guidelines for coal-fired power plants in China; ©WFGD has the highest CPM inorganic component removal radio of 97.02%, and ESP has the highest CPM organic component removal radio of 58.46%, among APCDs; ©SO4 2−, NH4 +, F−, and Cl− are the most abundant water-soluble ions in CPM.

Applicability of coal slag for application as packed bed thermal energy storage materials

Refractory materials are considered as the most suitable high-temperature sensible heat storage materials due to their excellent thermo-mechanical resistance and superior thermophysical properties. Unfortunately, refractories are usually too expensive. To reduce the cost of energy storage materials, the recycling of refractory industrial solid wastes into storage materials is becoming increasingly prevalent. The paper innovatively proposes to use the slags from a liquid slagging furnace of a coal-fired power plant in China as packed bed sensible heat energy storage materials. This paper characterizes the chemical compositions and thermophysical properties of three typical coal slags (Fukang coal slag, Fukang coal granulated slag, Hongshaquan coal granulated slag) and evaluates their potentials as storage materials. The results show that the three kinds of coal slags have good thermophysical properties. At 380 °C, the energy storage densities per unit volume of the three materials are 1037 MJ/m3, 986 MJ/m3 and 920 MJ/m3, respectively. Fukang coal slag has good thermal stability and durability and can be directly used for ultra-high temperature energy storage at 1000 °C. Due to the low crystallization degree, the two granulated slags have poor thermal durabilities and need to be processed at high temperatures before using them for energy storage applications.