Article pubs.acs.org/est
Nitrogen Oxides Emissions from Thermal Power Plants in China: Current Status and Future Predictions Hezhong Tian,*,† Kaiyun Liu,† Jiming Hao,‡ Yan Wang,† Jiajia Gao,† Peipei Qiu,† and Chuanyong Zhu† †
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China ‡ Institute of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China S Supporting Information *
ABSTRACT: Increasing emissions of nitrogen oxides (NOx) over the Chinese mainland have been of great concern due to their adverse impacts on regional air quality and public health. To explore and obtain the temporal and spatial characteristics of NOx emissions from thermal power plants in China, a unitbased method is developed. The method assesses NOx emissions based on detailed information on unit capacity, boiler and burner patterns, feed fuel types, emission control technologies, and geographical locations. The national total NOx emissions in 2010 are estimated at 7801.6 kt, of which 5495.8 kt is released from coal-fired power plant units of considerable size between 300 and 1000 MW. The top provincial emitter is Shandong where plants are densely concentrated. The average NOx-intensity is estimated at 2.28 g/kWh, markedly higher than that of developed countries, mainly owing to the inadequate application of high-efficiency denitrification devices such as selective catalytic reduction (SCR). Future NOx emissions are predicted by applying scenario analysis, indicating that a reduction of about 40% by the year 2020 can be achieved compared with emissions in 2010. These results suggest that NOx emissions from Chinese thermal power plants could be substantially mitigated within 10 years if reasonable control measures were implemented effectively.
1. INTRODUCTION Anthropogenic nitrogen oxides (NOx = NO + NO2) emissions are associated with significant impacts on ecosystems and human health, including an increase in ground-level ozone, formation of fine particles, and regional acid deposition.1−3 Local and regional photochemical smog and fine particulate (PM10/PM2.5) formation, along with very high local NOx/NO2 concentrations, are considered as severe environmental problems in China.4−6 In addition, the variation of [SO42−/ NO3−] ratio in precipitation composition reveals that acid deposition in many regions has been changing from a typical sulfate-controlled type to sulfate-and-nitrate-controlled type.7 Since 2005, in order to fulfill the rising electricity demand from industrial and residential consumers, hundreds of large electricity generator units have been built throughout China. As a result, coal used for electric generation has amounted to 1591 Mt, accounting for about 50% of national total coal consumption, which results in a large amount of SO2 and NOx emissions.8−10 Fortunately, the total SO2 emissions from power plants have been reduced gradually through wide application of flue gas desulfurization (FGD) and substitution of lower sulfur fuels during the “11th five-year-plan (2006− 2010)”, but fewer actions have been taken to diminish NOx emissions, leading to worsening NOx pollution as electric generation expands. © 2013 American Chemical Society
During the past two decades, a series of studies on anthropogenic NOx emission inventories have been conducted, indicating that the power plants sector accounts for 21−44% of Chinese national NOx emissions.6,11−19 Consequently, the power plant sector is regarded as the first priority for NOx emissions reduction in the Chinese national 12th five-year-plan (2011−2015). A rigorous goal of 29% NOx reduction compared with emissions in 2010 from thermal power plants for the target year 2015 has been set by the Chinese central government.20,21 To obtain an understanding of NOx emissions from the power plant sector for policy making, the current temporal and spatial distribution characteristics of NOx emissions released from power plants, as well as the trends in the near future, are investigated in this study.
2. METHODOLOGY, DATA SOURCES, AND KEY ASSUMPTIONS In this article, a new unit-based bottom-up methodology is established to estimate NOx emissions according to an Received: Revised: Accepted: Published: 11350
May 16, 2013 September 4, 2013 September 6, 2013 September 6, 2013 dx.doi.org/10.1021/es402202d | Environ. Sci. Technol. 2013, 47, 11350−11357
Environmental Science & Technology
Article
Table 1. NOx Emission Factors for Different Types of Pulverized Coal Boilers (g/kg) with LNBS
non-LNBS
unit size
burner pattern
bituminous/lignite
anthracite/lean coal
bituminous/lignite
anthracite/lean coal
