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This study endeavors to enhance the operational efficiency of extant coal-fired power plants to mitigate the adverse environmental impact intrinsic to the prevalent utilization of coal-fired power generation, which is particularly dominant in China. It focuses on the assessment and optimization of continuous denitrification systems tailored for a 1000 MW ultra-supercritical pulverized coal boiler. The extant denitrification framework encounters challenges during startup phases owing to diminished selective catalytic reduction (SCR) inlet flue gas temperatures. To ameliorate this, three retrofit schemes were scrutinized: direct mixing of high-temperature flue gas, bypass flue gas mixing, and high-temperature flue gas mixing with cold air. Each option underwent meticulous thermodynamic computations and comprehensive cost analyses. The findings elucidated that bypass flue gas mixing, involving the extraction and blending of high-temperature flue gas, emerged as the most financially prudent and practical recourse. This scheme optimizes fuel combustion heat utilization, significantly curtails fuel consumption, and fosters efficient internal heat transfer mechanisms within the boiler. The evaluation process meticulously considered safety parameters and equipment longevity. The insights derived from this investigation offer valuable guidance for implementing continuous denitrification system retrofits in industrial coal-fired power plants. [ABSTRACT FROM AUTHOR]

Abstract Sulfur trioxide (SO 3) pollution is becoming another severe problem in coal-fired power plants after SO 2 , NOx, and PM, however, the characteristics of SO 3 emission in China remains unclear. In this paper, we established a refined activity data, and summarized the removal efficiency of different control technologies according to the literature review and field test results. An emission inventory of SO 3 from coal-fired power plants in China between 2009 and 2014 was developed, which indicated the SO 3 emission increased from 199.7 kilotons (kt) to 314.6 kt at an average annual growth rate of 9.7%. The results show that Neimenggu, Shānxi, Jiangsu, Shandong, Guangdong and Guizhou were the largest emitters, accounting for 49.7% of the total SO 3 emissions in 2014. We analyzed the historical data with ArcGIS system, which allocates the emission into 36 km × 36 km grid cells. In addition, the result shows the unevenly spatial distribution. Combined with future economic development as well as implementation of policy, three different scenarios were set to project SO 3 emission in coal-fired power plants in 2020, which represented the potential of SO 3 emission reduction. Compared with scenario A, SO 3 emission can be reduced to 83.9 kt in scenario B, and in scenarios C, SO 3 emission can be reduced to 38.4 kt. Coal-fired power plants should adopt different technology routes to meet the ultra-low emission requirement and reduce the SO 3 emission according to the boiler type, sulfur content, and the emission standard. Highlights • The first SO 3 emission inventory of coal-fired power plants developed in the Period 2009–2014 in China. • Variations in regions and source characteristics were investigated and analyzed. • Uncertainties of inventory were assessed in a quantitative way. • Scenarios were set to project SO 3 emission for the year 2020, which present the potential of the emission reduction. [ABSTRACT FROM AUTHOR]

Aiming at enhanced particulate matter (PM) removal of electrostatic precipitators (ESPs) in coal-fired power plants, a pulse energization power supply that generates high-voltage pulses superimposed on a high-voltage dc was designed. The integrated theories of corona discharge, particle charging, and removal were presented, and the pulse energization strategy was studied through fractional particle removal simulation. The conclusion of simulation stated that pulse energization could significantly improve particle charge with a maximum enhancement at a particle diameter of $20~\mu \text{m}$ , while the fractional particle removal efficiency shows a different distribution that removal of particles less than $2.5~\mu \text{m}$ had the most significant enhancement. Based on the design and simulations, a full-scale comparative operation study testified the potential of dc + pulse energization to enhance particle removal with a limited power consumption increase. Pulse energization was applied to different industrial ESPs with various design and operation parameters and shown multicondition adaptability in PM removal enhancement, with the emission reduction ranging from 45.48% to 58.00% and outlet concentration from 8.60 to 47.48 mg/Nm3, proving it a convenient and economical method in the performance boost of industrial ESPs. [ABSTRACT FROM AUTHOR]

The life cycle environmental impacts of widely used flue-gas cleaning processes, including limestone-gypsum wet flue-gas desulfurization (FGD), selective catalytic reduction denitration (SCR) and electrostatic precipitators (ESP), are compared. The abbreviations FGD, SCR and ESP in this article refer in particular to the above listed processes. Energy consumption, resource consumption and emission inventories of each life cycle phase are established. The potentials of five environmental impact categories, namely, global warming, acidification, nutrient enrichment, photochemical ozone formation, soot and ashes are finally obtained. The current paper reveals that the total energy consumption and resource consumption are dominated by the process operation. The three processes are compared and it is found that to achieve equal environmental burden reductions, the SCR process consumes more energy and approximately the same amount of air and inert rock as the FGD. But the water consumption of the FGD is much higher than the SCR. The ESP process consumes both the least energy and the least resource in general. The economic assessment indicates that the performance of the ESP process tends to be the best and the FGD follows when equally invested. [ABSTRACT FROM AUTHOR]

The environmental issue of SO 3 pollution caused by coal-fired power plants attracts increasing attention. This work focused on the synergies between air pollution control devices in a 660 MW power plant burning high-sulfur coal. Parameters such as gas temperature and flow rate were varied within wide ranges under actual conditions. Both continuously tested SO 3 concentration and on-line operational data were combined to establish a correlation between device performance and operational parameter. Results indicated that the gas temperature acted as a bridge of synergies between the electrostatic precipitator (ESP) and wet electrostatic precipitator (WESP). The SO 3 removal efficiency across the ESP increased from 60.3% to 91.1% with the gas temperature decreasing from 136.7 to 114.8 °C, leading to the increase in corona current and the decrease in spark-over frequency of WESP. Moreover, additional electric field stages are also effective to enhance the corona current and reduce spark-over frequency. Furthermore, deviations between the design and operational data within 0–100% loading provided a correction to appropriately choose the gas velocity. With the proposed countermeasures, the SO 3 emission can achieve a favorable level less than 5 mg/m3. The research findings provide a valuable technical pathway to eliminate the SO 3 emission from power plants burning high-sulfur coal. Image 1092559 • A full-scale 660 MW power plant burning high-sulfur coal was investigated. • SO 3 effects on synergies among air pollution control devices were analyzed. • The gas temperature acted as a bridge of synergies between the ESP and the WESP. • Deviations were provided to guide the design and operation. • SO 3 emissions less than 5 mg/m3 can be realized with synergetic methods. [ABSTRACT FROM AUTHOR]

• Energy-cyber-physical-systems improve flexibility in fuel sources & energy products. • Quantitative analysis of improvement in coal-sludge co-combustion is conducted. • Quantitative thermodynamic and economic assessments are conducted. • The heating, cooling, power and compressed air products are stably produced. • Artificial neural network is employed for the prediction of realistic scenarios. The fluctuating energy requirement from time-varying demand changes require flexible power system to respond to the dynamic load balance. In certain scenarios, flexible power systems are necessary to provide high system efficiencies and increase the long-term economic benefits. Therefore, it is important to identify the relationship between energy requirement of a city and/or industrial zone with the dynamics of a flexible power system. In this paper, we evaluate the possible benefits of adopting the energy-cyber-physical-systems (e-CPSs) concept in realization of a flexible closed-loop control power system in case of coal-sewage sludge co-combustion. The case study performance analysis of flexibility, efficiency and economics (FEE) for a 356 MW coal-fired power plant was conducted by means of simulation in Aspen PLUS software. The analysis was based on a specific multifarious model of a dynamic power system with two energy sources and four energy products. The results confirmed that substantial advantages including a more flexible, efficient and economically viable system can be achieved by using e-CPSs based solution in different case scenarios. Moreover, following the analyzed data from the proposed case scenarios, a forecasting model for optimization of the power plant parameters based on the use of artificial neural network (ANN) was established. The results showed that ANN-based approach for predictive model is capable of modelling the complex process within an acceptable prediction accuracy. The study demonstrates that the proposed flexible closed-loop control power system based on e-CPSs concept is able to achieve higher efficiency and economic benefits compared to the traditional approaches. [ABSTRACT FROM AUTHOR]