Typical Coal-fired Power Plant Research Articles

Magnetite nanoparticles from representative coal fired power plants in China: Dust removal capture and their final atmospheric emission

Information on the emission of coal combustion-sourced magnetite nanoparticles (MNPs) is lacking, which is critical for their health-related risks. In this study, MNPs in coal fly ashes (CFAs) from various coal-fired power plants (CFPPs) in China equipped with various dust removal devices were extracted and quantified using single particle ICP-MS. The number concentrations of MNPs in CFAs captured by dust removal increased with stage, while their size decreased. Among all the dust removal devices, electrostatic-fabric-integrated precipitators showed the best removal of MNPs. Furthermore, throughout all the coal combustion by-products in a typical CFPP, MNPs in EFA (fly ash escaped from the stack) showed the highest number concentration (1.2 × 107 particles/mg) and lowest size (78 nm). Although the mass of CFA escaping through the stack is extremely low, it still had an emission rate of 1.9 × 1015 particles/h, contributing 3.56 % of the total emissions of MNPs in number. In addition, the purity of MNPs and their associated toxic metals showed a size-dependent variation pattern. As the particle size of MNPs decreased, the proportion of Fe in MNPs increased from 43 % in bottom ash (BA) to 84 % in EFA, while the abundance of trace toxic metals in EFA was 3.3 times higher than that of BA. These MNPs with the highest purity can adsorb elevated concentrations of toxic metals, and can be discharged directly into the atmosphere, posing a risk of synergistic toxicity.

Emissions of volatile organic compounds from Chinese coal-fired power plants: Characteristics, source profile, inventories, and impacts

Volatile organic compounds (VOCs) are key precursors for secondary organic aerosols (SOA) and ozone, imposing severe impacts on human health and environment. Considering the massive coal consumption, coal fired power plants (CFPPs) in China are non-negligible VOCs contributors, whose emission characteristics remain inadequately understood. Here, we investigated emission characteristics of 117 VOCs by field tests in four typical CFPPs, and a latest localized CFPPs source profile was compiled by integrating literature reviews. Then speciated-VOCs emission inventories for 2018–2022 were established based on dynamic emission factors and unit-level activity data. The results suggested that oxygenated VOCs (OVOCs) constituted the dominant group (76.5 %), with propionaldehyde (32.0 %) and formaldehyde (24.5 %) being the predominant species. OVOCs (93.2 %) and aromatics (77.4 %) were identified as the primary contributors to ozone and SOA, respectively. Driven by both the rise in coal consumption and technological advancements, nationwide VOCs emissions decreased from 83,393 t in 2018 to 53,251 t in 2022. Regional disparities and varying rates of decline in provincial emissions were evident, with VOCs emissions predominantly concentrated in northern and eastern provinces. Neimenggu, Shandong, Shanxi, Jiangsu, and Guangdong were identified as the top five provinces with the highest emissions. We believe this study would be conducive to a more comprehensive understanding and effective control of VOCs emissions from CFPPs in China.

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.

Heavy metal levels in the soil near typical coal-fired power plants: partition source apportionment and associated health risks based on PMF and HHRA.

In this study, five priority metals recommended by the Ministry of Ecology and Environment of China (MEEC) were investigated. In the Bijie region of Guizhou Province, three typical coal-fired power plants were chosen as the research locations. A combination of 24 soil samples was obtained at various distances and depths from the point source of contamination. The authors found that the average contents of As, Cd, Cr, Ni, and Pb were 14.15, 1.52, 16.80, 40.71, and 53.00mgkg-1, respectively, with Cd and Pb pollution prominent. In another, soil heavy metal (SHM) content tends to increase or decrease dependently with the increase of sampling distance and depth, with total concentrations ranging from 77.14 to 157.33mgkg-1. Combining PCA and PMF models, the number of source factors was determined more clearly and accurately using PCA, and the Q-value of PMF was used for validation. The PCA-PMF indicated that the primary anthropogenic sources were transportation-related activities and emissions from coal combustion. The health risks of SHMs under three different exposure routes were then assessed using the HHRA. The findings showed the five HMs in order of non-carcinogenic risk were As > Pb > Cr > Ni > Cd. The comprehensive non-carcinogenic risk for children under the oral intake route around plant B and C was greater than 1, pointing to a potential health risk to children from the soils. The carcinogenic risk of HM was less than 1.00E-04 for both single-factor and multifactor under all three exposure routes, which is below the tolerable limit.

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.

Differentiated emission control strategy based on comprehensive evaluation of multi-media pollution: Case of mercury emission control

In order to comprehensively evaluate the environmental impact of multi-media mercury pollution under differentiated emission control strategies in China, a literature review and case studies were carried out. Increased human exposure to methylmercury was assessed through the dietary intake of residents in areas surrounding a typical coal-fired power plant and a zinc (Zn) smelter, located either on acid soil with paddy growth in southern China, or on alkaline soil with wheat growth in northern China. Combined with knowledge on speciated mercury in flue gas and the fate of mercury in the wastewater or solid waste of the typical emitters applying different air pollution control devices, a simplified model was developed by estimating the incremental daily intake of methylmercury from both local and global pollution. Results indicated that air pollution control for coal-fired power plants and Zn smelters can greatly reduce health risks from mercury pollution, mainly through a reduction in global methylmercury exposure, but could unfortunately induce local methylmercury exposure by transferring more mercury from flue gas to wastewater or solid waste, then contaminating surrounding soil, and thus increasing dietary intake via crops. Therefore, tightening air emission control is conducive to reducing the comprehensive health risk, while the environmental equity between local and global pollution control should be fully considered. Rice in the south tends to have higher bioconcentration factors than wheat in the north, implying the great importance of strengthening local pollution control in the south, especially for Zn smelters with higher contribution to local pollution.

Adsorption of low-concentration organic pollutants from typical coal-fired power plants by activated carbon injection

Activated carbon (AC) injection was applied to remove the organic pollutants from coal-fired power plants. The total hydrocarbon (THC) concentration in flue gases was 0.512–0.998 mg/m3, aromatic hydrocarbons and oxygenated volatile organic compounds (VOCs) were the major components. With the AC injection (150 mg/m3), the THC was removed by 36.52–46.49%. The mesopores could capture some larger organic molecules and facilitate the intrapore diffusion. Improving the AC injection amount promoted the organic pollutant adsorption, but lowered the AC adsorption capacity. Removal performance of organic pollutants was affected by their physicochemical properties. The removal efficiency for most VOCs was within the range of 15–50%, while that was 45–90% for semi-VOCs. Minor amounts of VOCs achieved high removal efficiency through specific interactions, especially oxygenated VOCs. However, the removal efficiency of the total oxygenated VOCs was lower due to competition adsorption with inorganic components. AC injection had no significant effect on the physicochemical properties of fly ash. This work and results provide a feasible method and reference for the reduction of organic pollutants in coal-fired power plants and other combustion exhaust gases.

Investigation on the ammonia emission characteristics in coal-fired power plants of China

The coal-fired power plants in China have basically completed the upgrade and transformation for the ultra-low emission, and the reduction in traditional pollutant emission is significant. However, excessive ammonia emission has become one of the major concerns due to its adverse effects on environmental protection facilities and atmospheric environment. In this paper, four typical coal-fired power plants which have completed the ultra-low emission retrofits were measured on site to investigate the whole process emission characteristics of ammonia. The ammonia in the flue gas was classified into the gaseous ammonia, the filterable ammonia or the total ammonia, based on different sampling systems. Besides, the ammonia in the captured fly ash, desulfurization slurry, desulfurization wastewater, and gypsum was also analyzed to provide a quantitative overview of ammonia emission. Results showed that there was only gaseous ammonia detected at the outlet of SCR devices. Most gaseous ammonia was converted into filterable ammonia when it passed through the air preheater. Filterable ammonia, the predominant form of ammonia that made up about 65% to 95% of the total ammonia, could be effectively captured by the dust removers, with over 80% of it being removed. Higher ammonia concentration was measured from the fly ash collected in the rear storehouses. The concentration of ammonia emitted at the WFGD outlet was less than 0.5 mg/Nm3, with no more than 0.3 mg/Nm3 being discharged after the further removal by WESP. Discharging with the captured fly ash was the main pathway for ammonia emission, which should be considered in the further pollution control in coal-fired power plants.

Pisussion on noise exposure level measurement and risk assessment of typical posts in coal-fired power plants

Objective: To study the group noise exposure level of typical coal-fired power plants and explore the establishment of risk assessment methods for noise exposed posts. Methods: In April 2020, 295 typical workers in 11 coal-fired power plants were selected as the study subjects. The noise exposure dose of typical posts and the proportion of exposure groups under different exposure doses were analyzed, and the risk assessment based on the dose-response relationship was conducted. Results: The exposure level of typical noise posts in coal-fired power plants was (84.24±4.10) dB (A) , and the over-standard rate was 44.07% (130/295) . The highest noise over-standard rate in main posts were desulfurization inspectors (51.52%) , followed by steam turbine inspectors (47.92%) and belt inspectors (46.32%) . Taking 30 years as an example, the incidence rate of occupational noise deafness of noise-exposed posts in coal-fired power plants was 12.30%. The position with the highest incidence rate was belt inspector (13.21%) , followed by steam turbine inspector (12.97%) , desulfurization inspectors (12.42%) , boiler inspectors (11.59%) and chemical water inspectors (6.89%) . Conclusion: The risk of noise exposure in coal-fired power plants is relatively high. Comprehensive control measures are recommended to effectively reduce the risk of noise deafness.

Can efficiency evaluation be applied to power plant operation improvement? A combined method with modified weighted russell directional distance model and pattern matching

When there is no further potential to be gained from technological upgrading, it is crucial for coal-fired power plants to effectively utilize their input fuels to improve their operational efficiency and reduce emissions. This paper proposes a coal management model that combines modified weighted russell directional distance model and pattern matching to help coal-fired power plants improve their operation while finding more potential for energy saving and emission abatement. An operational strategy base is established by using efficiency evaluation results for unit daily operational data, and feasible coal blending schemes are accordingly located in the strategy base for different load conditions. The model measures the improvement potential from three perspectives: coal blending, coal input and load dispatching. The daily operational data of four units (two units with circulating fluidized bed (CFB) boilers and two sub-critical units) in a typical coal-fired power plant were collected for case study, and the results indicate that our model can provide effective decision support in plants’ operational management to achieve efficiency improvement.

Whole life cycle performance evolution of selective catalytic reduction catalyst in coal-fired power plants

Four typical coal-fired power plants were employed to explore the performance evolution within the whole life cycle of catalysts. The results revealed that the amount of active ingredients in the catalysts decreased over time. The content of V2O5 and WO3 in four units had decreased by 3.32%–32.8% and 12.9%–22.9% respectively. However, alkali metals and alkaline earth metals in flue gas were gradually deposited on the catalyst and led to catalyst poisoning, especially in two units due to arsenic poisoning. The specific surface area of catalysts decreased significantly in the first year of operation, accounting for 87.3%, 47.8%, 55.1% and 86.7% of the decline in the lifetime, which may be the main reason for the decline of catalyst activity during this period. The wall thickness of catalysts decreased linearly with the operation time in the lifetime. The relative activity of catalysts at the end of designed service lifetime was between 0.90 and 0.93, whereas the decrease range of SO2/SO3 conversion rate was within 15.4%–35.6%. Influenced by the catalyst design and the variations of practical operation conditions, the difference between the actual and designed service lifetimes of catalysts in the four units was 2.08%, 44.0%, 4.17%, and − 25.0%, respectively.

Emission characteristics of condensable particulate matter and sulfur trioxide from coal-fired power plants

Non-criteria air pollutants, namely, sulfur trioxide (SO3) and condensable particulate matter (CPM), are attracted more attention due to the non-negligible emission. In this work, the migration and emission characteristics of SO3 and CPM were investigated in two typical coal-fired power plants using the isopropanol absorption method and the dry impinger method, respectively. One of the power plants was equipped with two-stage wet flue gas desulfurization (WFGD) and the other one was self-generation power plant using Zhundong coal equipped with one-stage WFGD. The mass concentrations of SO3 and CPM were measured at the inlet and outlet of the air pollution control devices. To further understand the removal characteristics, the chemical compositions in organic and inorganic fractions of CPM were analyzed. Based on the measurement data, the emission factors of CPM and SO3 were calculated. The final emissions of SO3 range from 2.16 to 2.29 mg•Nm−3 and the emission factor is 0.024–0.040 kg/(t of coal). The stack emissions of filterable particulate matter all meet the ultra-low emission standard and are less than 5 mg•Nm−3. However, CPM emissions all exceed 10 mg•Nm−3 and account for more than 85% in total particulate matter. CPM concentrations are notable and the emissions should not be ignored. In both power plants, WFGD and wet electrostatic precipitator can reduce the emission of organic fraction in CPM; while one-stage WFGD has negative effect on the mitigation of inorganic fraction in CPM with the concentrations of water-soluble ions NH4+, SO42- and Cl− increasing by 41.37%, 52.22% and 91.73%, respectively.

Source profile and health risk assessment of PM2.5 from coal-fired power plants in Fuxin, China.

In order to improve and establish the localized source profile of PM2.5 in Fuxin, the ashes under dust catcher were collected from four typical coal-fired power plants in Fuxin and twenty-eight components were measured. The source profile of PM2.5 in the soot of the four coal-fired power plants was established. SO42- was the most abundant component in the PM2.5 of the soot of the four coal-fired power plants, followed by Ca2+ and organic carbon (OC). The content of element components in PM2.5 smoke ranges from 5.06 to 10.97%, the content of ionic components ranges from 36.53 to 48.59%, and the total carbon content ranges from 9.43 to 11.36%. The divergence coefficient of PM2.5 source profile in Fuxin coal burning smoke is mostly similar to that of Fushun, whereas the divergence coefficient of Colorado reaches 0.65, indicating that Fuxin coal burning power plant smoke has no similarity to Colorado. The order of the geological accumulation index of Ni, Cu, V, Mn, and Cr was Cr (4.58) > Mn (4.42) > V (4.38) > Cu (4.09) > Ni (4.06), showing a heavy pollution level. The health risk assessment model recommended by the USEPA was used to assess the health risk of heavy metals in soot of coal-fired power plants, and the non-carcinogenic risk values of As for children and adults were 45.7 and 4.90, respectively. The carcinogenic risk values of Cr for adults and children were the highest, with values of 3.66 × 10-5 and 2.06 × 10-5, respectively, followed by As.

Measurement of Radon Concentration and Estimation of Its Emission of Coal-Fired Power Plants

In the experiment, RAD7 multi-functional electronic radon meter was used to measure the radon (222Rn) concentration at key points in the production process of three typical coal-fired power plants in Hunan, Hubei and Jiangxi provinces along the Yangtze river in China. The results show that after the combustion of raw coal, the radon was released, which caused radon concentration after the boiler’s gas system to be significantly higher than the air intake. Combined with the measurement and survey data, two different estimation methods of radon emission were established. First, based on radon concentration measured on site and the air volume at each inlet and outlet, the normalized radon emission of three coal fired power plants are calculated to be 102 GBq/GWa order of magnitude. The second one is using activity concentration of 226Ra in combination with actual coal use to calculate the emission, in this way, that typical value of normalize radon emission 151.3 GBq/GWa is obtained. This study provides data support for the construction of nuclear power plants in inland China.

Characteristics of condensable particulate matter before and after wet flue gas desulfurization and wet electrostatic precipitator from ultra-low emission coal-fired power plants in China

Total particulate matters emitted from coal-fired power plants generally include condensable particulate matter (CPM) and filterable particulate matter (FPM). Based on the on-site sampling of CPM, this study investigated four typical coal-fired power plants equipped with ultra-low emission facilities in north China. In order to clarify the characteristics of CPM before and after wet flue gas desulfurization (WFGD) and wet electrostatic precipitator (WESP), the mass concentrations, organic and inorganic compositions of the CPM were analyzed. Among the four test power plants, the emission concentrations of CPM were 2.20–7.33 mg/Nm3, accounting for 57.74–91.79% of PM2.5. The organic component accounted for 59.64% of the total mass concentration of CPM on average. Alkanes, esters and amides were the major organic components. And the water-soluble ions contributed significantly to the inorganic component of CPM. The proportion of SO42− was the highest, followed by Cl− and NO3−. In addition, this study found that the concentration of SO42− increased significantly while SO3 decreased from WESP inlet to outlet. It was indicated that ultrafine particles and soluble SO2 in flue gas could contribute to the formation of SO42− in CPM besides SO3. As an important part of CPM, further studies should be conducted on the factors affecting SO42−.

Non-Negligible Stack Emissions of Noncriteria Air Pollutants from Coal-Fired Power Plants in China: Condensable Particulate Matter and Sulfur Trioxide.

In this study, we investigated the emission characteristics of condensable particulate matter (CPM) and sulfur trioxide (SO3) simultaneously through ammonia-based/limestone-based wet flue gas desulfurization (WFGD) from four typical coal-fired power plants (CFPPs) by conducting field measurements. Stack emissions of filterable particulate matter (FPM) all meet the Chinese ultralow emission (ULE) standards, whereas CPM concentrations are prominent (even exceed 10 mg/Nm3 from two CFPPs). We find that NH4+ and Cl- increase markedly through the ammonia-based WFGD, and SO42- is generally the main ionic component, both in CPM and FPM. Notably, the occurrence of elemental Se in FPM and CPM is significantly affected by WFGD. Furthermore, the established chemical profiles in FPM and CPM show a distinct discrepancy. In CPM, the elemental S mainly exists as a sulfate, and the metallic elements of Na, K, Mg, and Ca mainly exist as ionic species. Our results may indicate that not all SO3 are included in CPM and they co-exist in stack plume. With the substantial reduction of sulfur dioxide (SO2), S distributed in SO3, CPM, and FPM becomes non-negligible. Finally, the emission factors of CPM and SO3 under typical ULE technical routes fall in the ranges of 74.33-167.83 and 48.76-86.30 g/(t of coal) accordingly.

Hollow fiber-based rapid temperature swing adsorption process for carbon capture from coal-fired power plants

Post-combustion carbon capture is one of the feasible methods to reduce emission of carbon dioxide (CO2) from coal-fired power plants. The biggest challenge in this technology is reduction of energy consumption. This work proposes a hollow fiber based rapid temperature swing adsorption (RTSA) method for capturing CO2 from typical coal-fired power plants. The proposed RTSA approach can shorten the operating time and using low-grade energy for regeneration of adsorption elements. In this study, the tank-in-series model is used to simulate the RTSA process including adsorption and desorption periods. A dual-column operating procedure is then used to treat the flue gas continuously from the coal-fired power plants. Main operating variables including inlet gas volume flow rate (0.1–0.2 m3/s), abandon time (0–10 s), desorption temperature (80–120 °C) on key performance factors such as discharge gas purity, capture ratio of CO2, and energy consumption per unit CO2, etc. are investigated for reducing the energy consumption. This study found that the inlet gas volume flow rate will significantly affect the capture ratio, where smaller gas volume flow rate would be beneficial to increase capture ratio. The abandon time obviously affects the purity of the captured CO2, where the longer abandon time leads to higher purity. Desorption temperature affects both the capture ratio and purity of captured CO2. The higher the desorption temperature, the greater the purity and capture ratio. For one typical basic unit with dual-column hollow fiber-based RTSA, the study found that when the inlet gas volume flow rate is 0.12 m3/s, the desorption waiting time is 7 s, and the desorption temperature is 120 °C, both the CO2 purity and capture ratio can exceed 90%. With considering the possibility of using steam in a low-pressure turbine as a source of heat required for Dual column vacuum RTSA (DC-vRTSA), the impact on the efficiency and stream data of typical coal-fired power plants are calculated. DC-vRTSA at 120 °C, 100 °C and 80 °C will reduce the efficiency of coal-fired power plants by 8.2%, 6%, and 3.4%, respectively.

Forward ultra-low emission for power plants via wet electrostatic precipitators and newly developed demisters: Filterable and condensable particulate matters

Coal-fired power plants (CFPPs) install wet electrostatic precipitators (WESPs) or/and demisters as end control devices along with wet flue gas desulfurization (WFGD) systems to meet the ultra-low emission standards in China. This study comprehensively explores the influence of these end control devices on filterable particulate matter (FPM) and condensable particulate matter (CPM) emissions, based on field measurements and chemical analyses of collected samples. The field study was conducted in two typical CFPPs, one equipped with WESPs and the other with newly developed demisters (NDDs). With respect to FPM and filterable PM2.5, the WESP removal efficiency was 96 ± 3% and 92 ± 2%, respectively, and that of NDD was 62 ± 6% and 51 ± 5%, respectively. However, for some unconventional pollutants, the NDD removal efficiency was 60 ± 8% for CPM, which was higher than that of WESP (42 ± 10%); the removal efficiencies of HCl, SO3, and NH3 during the WESP were 78 ± 8%, 44 ± 11%, and 30 ± 5%, respectively, while they were 69 ± 16%, 58 ± 9%, and 60 ± 7%, respectively, when equipped with the NDD. Chemical composition analysis of the obtained samples revealed that the relative content of SO42− in FPM2.5 increased from 12–17% to 14–33% on using end control devices (WESP or NDD). Moreover, SO42− was the major ion component in CPM with relative ratios increasing from 15–35% to 21–59%. The mass ratio of FPM2.5 in FPMs, as well as the relative mass ratio of CPMs, in total particulate matter increased at the outlets of both control devices. The obtained results imply that both WESP and NDD effectively remove FPM and CPM to meet the ultra-low emission standards, respectively. Thus, more attention should be paid to emissions of CPM and FPM2.5 in pollution control technologies.

Switching Coal-Fired Thermal Power Plant to Composite Fuel for Recovering Industrial and Municipal Waste: Combustion Characteristics, Emissions, and Economic Effect

Combustion characteristics were studied experimentally for single droplets of fuel slurries based on wet coal processing waste with municipal solid waste components (cardboard, plastic, rubber, and wood) and used turbine oil. We established the ignition delay time for three various groups of fuel compositions in motionless air at 600–1000 °C. The minimum values are 3 s, and the maximum ones are 25 s. The maximum temperatures in the droplet vicinity reach 1300 °C during fuel combustion for compositions with 10% of used oil. The combustion temperatures of fuel compositions without oil are 200–300 °C lower. The concentrations of anthropogenic emissions in flue gases do not exceed those from dry coal combustion. Adding used oils to composite fuels reduces the concentrations of dioxins and furans in flue gases when municipal solid waste in the fuel burns out due to high combustion temperatures. Based on the experimental research findings, we have elaborated a strategy of combined industrial and municipal waste recovery by burning it as part of composite fuels, as illustrated by three neighboring regions of the Russian Federation with different industrial structures and levels of social development. This strategy suggests switching three typical coal-fired thermal power plants (one in each of the regions) to composite liquid fuel. It will reduce the hazard of waste to the environment and decrease the consumption of high-quality coals for power generation. Implementing the developed strategy for 25 years will save 145 Mt of coal and recover 190–260 Mt of waste. The positive economic effect, considering the modernization of fuel handling systems at thermal power plants and the construction of a fuel preparation plant, will make up 5.7 to 6.9 billion dollars, or 65–78%, respectively, of the main costs of three thermal power plants operating on coal within the identical period.

CO2 Emission Calculation and Emission Characteristics Analysis of Typical 600MW Coal-fired Thermal Power Unit

In order to effectively reduce the total CO2 emissions of coal-fired power plants and reduce greenhouse gas emissions, the relevant data of a typical 600MW coal-fired power plant in the past five years was collected and investigated, and CO2 emissions and emission intensity were calculated. And the results were used to measure the CO2 emission level of coal-fired power plants. By comparing and analyzing the CO2 emission intensity and emission trend of 600MW coal-fired units with different unit types and different fuel types, the CO2 emission characteristics of typical 600MW coal-fired power plants are obtained.