1
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Zhao H, Li W, Zhang J, Ding X, Kang Z. Retrofit and application of pulverized coal burners with LNG and oxygen ignition in utility boiler under ultra-low load operation. Heliyon 2024; 10:e29154. [PMID: 38638988 PMCID: PMC11024548 DOI: 10.1016/j.heliyon.2024.e29154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/16/2024] [Accepted: 04/02/2024] [Indexed: 04/20/2024] Open
Abstract
An oxygen-rich and low NOx burner integrated with liquefied natural gas (LNG) was proposed to address unstable combustion and high NOx emissions from a 330 MW subcritical boiler under ultra-low load operation in China. To assess the effectiveness of the retrofit, Chemkin and Fluent softwares were utilized to construct a new NOx model and calculate NOx generation, based on the combustion of pulverized coal gas and LNG. Further, an eddy dissipation concept (EDC) model, which can reflect detailed chemical reactions, was applied to calculate gas-phase reactions in the furnace. The results showed that when performing the deep peak shaving after the retrofit, the combustion in the furnace was stable under 50% or more load, and NOx emission level at the furnace outlet was lower than 350 mg/m3 (6% O2 content, dry basis). Under 25% load, the oxygen-rich burner integrated with LNG was applied, and the pulverized coal flow entered the furnace in a state of high-intensity combustion, which effectively promoted the stability of combustion in the furnace. The reductive combustion state with reductive free radicals generated by LNG decomposition inhibited NOx formation. Consequently, NOx emissions from the furnace outlet decreased from 380 mg/m3 to 316 mg/m3.
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Affiliation(s)
- Hujun Zhao
- CHN Energy Long Yuan Blue Sky Energy Conservation Technology Co., Ltd., Beijing 100039, China
| | - Weiqi Li
- GD Power Development Co., Ltd., Beijing 100101,China
| | - Jie Zhang
- School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, China
| | - Xian Ding
- Shanghai Power Equipment Research Institute Co., Ltd., Shanghai 200240, China
| | - Zhizhong Kang
- School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, China
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2
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Tian M, He L, Peng D, Fu M, Ma S, Mu J, Yu Q, Wang J, Yin H, Wang J. Characterizing NOx emissions from diesel trucks with tampered aftertreatment systems and its implications for identifying high emitters. Sci Total Environ 2024; 917:170378. [PMID: 38280581 DOI: 10.1016/j.scitotenv.2024.170378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/19/2024] [Accepted: 01/21/2024] [Indexed: 01/29/2024]
Abstract
Reducing the differences between real-world and certificated NOx emission levels is an important element of in-use emission surveillance programs. Therefore, investigating the characteristics of the vehicles which have much higher NOx emissions (i.e., high-emitters) and determining a reasonable cut-off point to identify high-emitters with a low false detection rate is important. In this study, six diesel trucks were tested under different aftertreatment conditions. The results showed that the discrepancies of fuel-specific NOx emissions between vehicles with functioning and tampered selective catalytic reduction (SCR) systems occur mainly from medium- to high-speed modes. This is because the SCR systems were at low conversion efficiencies when the exhaust temperature was low, including cold-start and urban creep conditions. By using binary classification, we selected fuel-specific NOx cut-off points for high-emitters from China V and China VI diesel trucks. The false detection rate of high-emitters can decrease by 33 % and 95 %, if only NOx emissions from medium- to high-speed modes were used for the chosen cut-off points, respectively. This work highlights the importance of in-use emission compliance programs. It also suggests that high-emitters can be more accurately identified at medium- to high-speed modes if using instantaneous emission data.
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Affiliation(s)
- Miao Tian
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Liqiang He
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Di Peng
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Mingliang Fu
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Shuai Ma
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Jinsong Mu
- Xiamen Environment Protection Vehicle Emission Control Technology Center, Xiamen 361023, PR China
| | - Quanshun Yu
- CATARC Automotive Test Center (Tianjin) Company Limited, Tianjin 300300, PR China
| | - Jia Wang
- Jinan Automobile Testing Center Co, Ltd., Jinan 250102, PR China
| | - Hang Yin
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Junfang Wang
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
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3
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Badami MM, Tohidi R, Sioutas C. Los Angeles Basin's air quality transformation: a long-term investigation on the impacts of PM regulations on the trends of ultrafine particles and co-pollutants. J Aerosol Sci 2024; 176:106316. [PMID: 38223364 PMCID: PMC10783618 DOI: 10.1016/j.jaerosci.2023.106316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
This study investigates the long-term trends of ambient ultrafine particles (UFPs) and associated airborne pollutants in the Los Angeles Basin from 2007 to 2022, focusing on the indirect effects of regulations on UFP levels. The particle number concentration (PNC) of UFPs was compiled from previous studies in the area, and associated co-pollutant data, including nitrogen oxides (NOx), carbon monoxide (CO), elemental carbon (EC), organic carbon (OC), and ozone (O3), were obtained from the chemical speciation network (CSN) database. Over the study period, a general decrease was noted in the PNC of UFPs, NOx, EC, and OC, except for CO, the concentration trends of which did not exhibit a consistent pattern. UFPs, NOx, EC, and OC were positively correlated, while O3 had a negative correlation, especially with NOx. Our analysis discerned two distinct subperiods in pollutant trends: 2007-2015 and 2016-2022. For example, there was an overall decrease in the PNC of UFPs at an annual rate of -850.09 particles/cm3/year. This rate was more pronounced during the first sub-period (2007-2015) at -1814.9 particles/cm3/year and then slowed to -227.21 particles/cm3/year in the second sub-period (2016-2023). The first sub-period (2007-2015) significantly influenced pollutant level changes, exhibiting more pronounced and statistically significant changes than the second sub-period (2016-2022). Since 2016, almost all primary pollutants have stabilized, indicating a reduced impact of current regulations, and emphasizing the need for stricter standards. In addition, the study included an analysis of Vehicle Miles Traveled (VMT) trends from 2007 to 2022 within the Los Angeles Basin. Despite the general increase in VMT, current regulations and cleaner technologies seem to have successfully mitigated the potential increase in increase in PNC. Overall, while a decline in UFPs and co-pollutant levels was observed, the apparent stabilization of these levels underscores the need for more stringent regulatory measures and advanced emission standards.
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Affiliation(s)
- Mohammad Mahdi Badami
- University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, California, USA
| | - Ramin Tohidi
- University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, California, USA
| | - Constantinos Sioutas
- University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, California, USA
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4
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Samosir BF, Quach NY, Chul OK, Lim O. NOx emissions prediction in diesel engines: a deep neural network approach. Environ Sci Pollut Res Int 2024; 31:713-722. [PMID: 38019409 DOI: 10.1007/s11356-023-30937-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/02/2023] [Indexed: 11/30/2023]
Abstract
The reduction of various nitrogen oxide (NOx) emissions from diesel engines is an important environmental issue due to their negative impact on air quality and public health. Selective catalytic reduction (SCR) has emerged as an effective technology to mitigate NOx emissions, but predicting the performance of SCR systems remains a challenge due to the complex chemistry involved. In this study, we propose using DNN models to predict NOx emission reductions in SCR systems. Four types of datasets were created; each consisted of five variables as inputs. We evaluated the models using experimental data collected from a diesel engine equipped with an SCR system. Our results indicated that the deep neural network (DNN) model produces precise estimates for exhaust gas temperature, NOx concentration, and De-NOx efficiency. Moreover, inclusion of additional input features, such as engine speed and temperature, improved the prediction accuracy of the DNN model. The mean absolute error (MAE) values for these parameters were 3.1 °C, 3.04 ppm, and 3.65%, respectively. Furthermore, the R-squared coefficient of determination values for the estimates were 0.912, 0.983, and 0.905, respectively. Overall, this study demonstrates the potential of using DNNs to accurately predict NOx emissions from diesel engines and provides insights into the impact of input features on the performance of the model.
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Affiliation(s)
- Bernike Febriana Samosir
- Graduate School of Mechanical Engineering, University of Ulsan, 93 Daehak-Ro, Nam-Gu, Ulsan, 44610, South Korea
| | - Nhu Y Quach
- Graduate School of Mechanical Engineering, University of Ulsan, 93 Daehak-Ro, Nam-Gu, Ulsan, 44610, South Korea
| | - Oh Kwang Chul
- Korea Automotive Technology Institute, 303 Chungcheongnam-Do, Dongnam-Gu, Pungse-Myeon, Pungse-Ro, Cheonan, South Korea
| | - Ocktaeck Lim
- School of Mechanical Engineering, University of Ulsan, 93 Daehak-Ro, Nam-Gu, Ulsan, 44610, South Korea.
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5
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Liu C, Pei Y, Wu C, Zhang F, Qin J. Novel insights into the NOx emissions characteristics in PEMS tests of a heavy-duty vehicle under different payloads. J Environ Manage 2023; 348:119400. [PMID: 37925984 DOI: 10.1016/j.jenvman.2023.119400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 09/24/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023]
Abstract
Real Drive Emission (RDE) test with Portable Emission Measurement System (PEMS) is a widely adopted way to assess vehicle emission compliance. However, the current NOx emissions calculation method stipulated in the China VI emission standard easily ignores the NOx emissions during cold start and low-power operation. To study the effect of cold start and low-power operation on the calculation of NOx emissions in the PEMS test, in this study, a China VI Heavy-Duty Vehicle (HDV) for urban use was used to conduct PEMS tests under various vehicle payload conditions. The data analysis results show that the increase in vehicle payload is beneficial to reducing the specific NOx emissions and passing the NOx emission compliance test because the increased payload improves the NOx conversion efficiency of the SCR system. Cold start duration has no obvious relationship with vehicle payload, accounting for only about 4∼6% in each test, but contributing more than 30% of NOx emissions. Due to the effect of the power threshold and the 90th cumulative percentile, the cold start data has little influence on the result of the NOx emissions assessment and the maximum variation of the NOx emissions result in this study is an 8% rise. For the HDV for urban use, the variation of the power threshold resulting from vehicle payload is small, no more than 2% in this study. The presence of the power threshold makes almost only the low-power operation in the second half of urban driving have an impact on the NOx emissions calculation, which may make more than 50% of NOx emissions in the PEMS test be neglected. The impact of the low-power operation on NOx emissions calculation result will be significantly enhanced if all windows are considered in the Moving Average Window (MAW) method. In the meantime, the degree of variation is closely related to the NOx emissions level during the first half of urban driving. The maximum deterioration of NOx emission assessment result can be more than 90% in this study.
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Affiliation(s)
- Chuntao Liu
- School of Mechanical Engineering, Tianjin University, Tianjin, China
| | - Yiqiang Pei
- School of Mechanical Engineering, Tianjin University, Tianjin, China.
| | - Chunling Wu
- School of Mechanical Engineering, Tianjin University, Tianjin, China; CATARC Automotive Test Center Company Limited, Tianjin, China
| | - Fan Zhang
- School of Mechanical Engineering, Tianjin University, Tianjin, China
| | - Jing Qin
- School of Mechanical Engineering, Tianjin University, Tianjin, China
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6
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Xu X, Zeng B. Application of a novel second-order differential equation grey model to forecast NOx emissions in China. Environ Sci Pollut Res Int 2023; 30:24441-24453. [PMID: 36342602 DOI: 10.1007/s11356-022-23662-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Nitrogen oxide (NOx) contains two harmful air pollutants: nitric oxide (NO) and nitrogen dioxide (NO2). The reasonable prediction of China's NOx emissions is of positive significance for the government to formulate environmental protection policies. To this end, a new grey prediction model with second-order differential equation is proposed in this paper, which has more reasonable model structure and better modeling performance than the traditional grey model. Secondly, according to the data characteristics of NOx emissions of China in recent years, a smoothing algorithm and weakening buffer operator are employed to process the original data to solve the rationality of the prediction results of the new model. Thirdly, the model for predicting China's NOx emissions has been constructed by the new proposed model. The results show that the mean comprehensive error of the new model is only 0.0692%, and its performance is much better than that of several other mainstream grey prediction models. Finally, the new model is applied to China's carbon dioxide prediction in the next 5 years, and the rationality of the prediction results is analyzed. Based on the prediction results, relevant countermeasures and suggestions are put forward.
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Affiliation(s)
- Xiaozeng Xu
- School of Mathematics and Statistics, Chongqing Technology and Business University, Chongqing, 400067, China
- Chongqing Key Laboratory of Social Economic and Applied Statistics, Chongqing, 400067, China
| | - Bo Zeng
- School of Management Science and Engineering, Chongqing Technology and Business University, Chongqing, 400067, China.
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7
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Lohwasser J, Schaffer A. The varying roles of the dimensions of affluence in air pollution: a regional STIRPAT analysis for Germany. Environ Sci Pollut Res Int 2023; 30:19737-19748. [PMID: 36239893 PMCID: PMC9938017 DOI: 10.1007/s11356-022-23519-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
STIRPAT models investigate the impacts of population, affluence, and technology on the environment, with most STIRPAT studies revealing positive impacts of both population and affluence. Affluence is commonly defined as GDP per capita, but investigations of its impact largely neglect the possibility that increasing prosperity affects the environment in varying-even opposing-ways. This study addresses this gap by decomposing affluence into three dimensions-income per taxpayer, private car ownership, and the share of single-family houses-and analyzing their roles in the production of local NOx emissions. Results for 367 German districts and autonomous cities between 1990 and 2020 indicate that, while private car ownership and single-family houses per capita can be considered drivers of local pollutants, such is not the case for income per taxpayer, which we find has a negative impact on NOx emissions. The empirical findings suggest that policies should strengthen integrated mobility concepts and establish incentives that favor investment in modern heating or self-sufficiency systems.
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Affiliation(s)
- Johannes Lohwasser
- Bundeswehr University Munich, Werner-Heisenberg-Weg 39, 85577, Neubiberg, Germany.
| | - Axel Schaffer
- Bundeswehr University Munich, Werner-Heisenberg-Weg 39, 85577, Neubiberg, Germany
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8
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Qiao J. A novel online modeling for NOx generation prediction in coal-fired boiler. Sci Total Environ 2022; 847:157542. [PMID: 35878857 DOI: 10.1016/j.scitotenv.2022.157542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/26/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
The selective catalytic reduction (SCR) denitration technology is widely used in coal-fired generating units. The NOx concentration of boiler outlet is an important parameter in the feedforward control of SCR denitration. However, its measurement lag leads to a large range fluctuation of NOx emission, which affects the safe and economic operation of the unit. In order to solve the problem of boiler outlet NOx concentration measurement lag in denitration control, and improve the timeliness of fluctuation response for denitration control. Many studies have reported on NOx concentration prediction models based on the long short-term memory (LSTM) algorithm, support vector machines (SVM) algorithm, et al. However, there are no reports on online modeling, particularly none on predictive values of boiler outlet NOx concentration ahead of the measured values. Thus, in this study, a 1000 MW ultra-supercritical coal-fired boiler was selected, and 2404 sets of measured samples were collected to predict NOx concentration. A novel online modeling method for NOx concentration of boiler outlet was proposed. For the first time, a high-precision online real-time prediction model of boiler outlet NOx concentration was innovatively established based on improved long short-term memory network (ILSTM). A feature quantity weight analysis method based on the RRelieff algorithm is adopted, and the change rates of feature quantities were used as input in the model. The results showed that the root mean square error (δR) and computation time of ILSTMN reduced relatively by 17.97 % and 1.97 s, respectively. The online model with satisfied accuracy is trained in 1 s, which uses the latest recent data from decentralized control system (DCS). The NOx concentration of boiler outlet predicted by the online model is 22 s ahead of the measurement NOx concentration, and the prediction accuracy is still as high as 96 % without the intervention after two years of operation. As a feedforward of SCR denitration control system, NOx concentration predicted by the model can significantly improve the timeliness of control response. The online model provides theoretical support for suppressing large fluctuations of NOx emissions.
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Affiliation(s)
- Jiafei Qiao
- CHN Energy New Energy Technology Research Institute Co., Ltd., Beijing 102209, China.
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9
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Pandey JK, M H D, G N K. Study of biomethanol as sustainable replacement of Autogas at variable ignition timing. Heliyon 2022; 8:e10865. [PMID: 36217462 DOI: 10.1016/j.heliyon.2022.e10865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/17/2022] [Accepted: 09/27/2022] [Indexed: 11/24/2022] Open
Abstract
Bio-methanol has recently interested researchers looking for a suitable alternative due to its low carbon/hydrogen (C/H) ratio. Adding methanol to Autogas could thereby improve combustion while lowering emissions. In the present investigation, testing is conducted at a compression ratio of 14:1 on various fuel ratios (55/45 to 75/25 with a 5% change) of methanol/Autogas with ignition timing ranging from 28°CA bTDC to 14°CA bTDC. The results indicate improvements due to the addition of 65% methanol. Improved brake thermal efficiency (BTE) by 6.27%, peak pressure (Pmax) by 0.36%, heat release rate (HRRmax), peak temperature (Tmax) by 0.89%, and rise in exhaust gas temperature (EGT). Simultaneously, combustion duration, HC & CO emissions, and the coefficient of variations in indicated mean effective pressure (CoVIMEP) are reduced. With methanol, the volumetric efficiency (ηvol) improves continuously. Optimal ignition timing is shown to advance with increasing methanol concentration. With ignition retard, the flame development phase (CA10) decreases by 1.7%/2°CA ignition retard, whereas the flame propagation phase (CA10-90) decreases to a minimum and then increases. Due to combustion instability, ignition retard increases the Cyclic variation and CoVIMEP, while Pmax, HRRmax, Tmax, and BTE increase to a maximum and then drop. Ignition retard is an effective way of reducing NOx emissions, although CO and HC emissions increase significantly. Due to reduced carbon supply, carbon emissions are extremely low even at higher methanol concentrations than Autogas-rich fuel. NOx emissions are also extremely low (62.5 % of the ignition angle at 24°CA), revealing that a higher methanol ratio could be used with minimal risk of power loss.
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10
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Xing J, Li S, Zheng S, Liu C, Wang X, Huang L, Song G, He Y, Wang S, Sahu SK, Zhang J, Bian J, Zhu Y, Liu TY, Hao J. Rapid Inference of Nitrogen Oxide Emissions Based on a Top-Down Method with a Physically Informed Variational Autoencoder. Environ Sci Technol 2022; 56:9903-9914. [PMID: 35793558 DOI: 10.1021/acs.est.1c08337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Accurate timely estimation of emissions of nitrogen oxides (NOx) is a prerequisite for designing an effective strategy for reducing O3 and PM2.5 pollution. The satellite-based top-down method can provide near-real-time constraints on emissions; however, its efficiency is largely limited by efforts in dealing with the complex emission-concentration response. Here, we propose a novel machine-learning-based method using a physically informed variational autoencoder (VAE) emission predictor to infer NOx emissions from satellite-retrieved surface NO2 concentrations. The computational burden can be significantly reduced with the help of a neural network trained with a chemical transport model, allowing the VAE emission predictor to provide a timely estimation of posterior emissions based on the satellite-retrieved surface NO2 concentration. The VAE emission predictor successfully corrected the underestimation of NOx emissions in rural areas and the overestimation in urban areas, resulting in smaller normalized mean biases (reduced from -0.8 to -0.4) and larger R2 values (increased from 0.4 to 0.7). The interpretability of the VAE emission predictor was investigated using sensitivity analysis by modulating each feature, indicating that NO2 concentration and planetary boundary layer (PBL) height are important for estimating NOx emissions, which is consistent with our common knowledge. The advantages of the VAE emission predictor in efficiency, flexibility, and accuracy demonstrate its great potential in estimating the latest emissions and evaluating the control effectiveness from observations.
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Affiliation(s)
- Jia Xing
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Siwei Li
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China
| | | | - Chang Liu
- Microsoft Research Asia, Beijing 100080, China
| | - Xiaochun Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Lin Huang
- Microsoft Research Asia, Beijing 100080, China
| | - Ge Song
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China
| | - Yihan He
- Mechanical Engineering Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Shuxiao Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Shovan Kumar Sahu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jia Zhang
- Microsoft Research Asia, Beijing 100080, China
| | - Jiang Bian
- Microsoft Research Asia, Beijing 100080, China
| | - Yun Zhu
- College of Environment and Energy, Guangzhou Higher Education Mega Center, South China University of Technology, Guangzhou 510006, China
| | - Tie-Yan Liu
- Microsoft Research Asia, Beijing 100080, China
| | - Jiming Hao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
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11
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Phantawesak N, Coyle F, Stettler MEJ. Long-Term In-Use NO x Emissions from London Buses with Retrofitted NO x Aftertreatment. Environ Sci Technol 2022; 56:6968-6977. [PMID: 34704747 DOI: 10.1021/acs.est.1c05083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Buses constitute a significant source of air pollutant emissions in cities. In this study, we present real-world NOx emissions from 97 diesel-hybrid buses measured using on-board diagnostic systems over 44 months and 6.35 million km in London. Each bus had previously been retrofitted with a selective catalytic reduction (SCR) aftertreatment system to reduce emissions of nitrogen oxides (NOx). On average, parallel hybrid (PH) and series hybrid (SH) buses emitted 3.80 g of NOx/km [standard deviation (SD) of 1.02] and 2.37 g of NOx/km (SD of 0.51), respectively. The SCR systems reduced engine-out emissions by 79.8% (SD of 5.0) and 87.2% (SD of 2.9) for the PHs and SHs, respectively. Lower ambient temperatures (0-10 °C) increased NOx emissions of the PHs by 24.2% but decreased NOx emissions of the SHs by 27.9% compared to values found at more moderate temperatures (10-20 °C). To improve emissions inventories, we provide new distance-based NOx emissions factors for different ranges of ambient temperature. During the COVID-19 pandemic, the emissions benefits of reduced congestion were largely offset by more frequent route layovers leading to lower SCR temperatures and effectiveness. This study shows that continuous in-service measurements enable quantification of real-world vehicle emissions over a wide range of operations that complements conventional testing approaches.
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Affiliation(s)
- Napameth Phantawesak
- Centre for Transport Studies, Department of Civil and Environmental Engineering, Imperial College, London SW7 2AZ, United Kingdom
| | - Finn Coyle
- Transport for London, Palestra House, London SE1 8NJ, United Kingdom
| | - Marc E J Stettler
- Centre for Transport Studies, Department of Civil and Environmental Engineering, Imperial College, London SW7 2AZ, United Kingdom
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12
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Shih JS, Driscoll CT, Burtraw D, Shen H, Smith RA, Keyes A, Lambert KF, Chen Y, Russell AG. Energy policy and coastal water quality: An integrated energy, air and water quality modeling approach. Sci Total Environ 2022; 816:151593. [PMID: 34808177 DOI: 10.1016/j.scitotenv.2021.151593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/05/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
Federal policy changes in the management of carbon emissions from power plants offer a potent real-world example for examining air-land-water interactions and their implications for coastal water quality. We integrate models of energy (Integrated Planning Model (IPM)), air quality (Community Multiscale Air Quality (CMAQ) and water quality (SPAtially Referenced Regression On Watershed attributes (SPARROW)) to investigate the potential water quality impacts of policy-driven changes in total nitrogen deposition in watersheds draining to US coastal areas. We estimate the combined effects of three recently proposed energy policy scenarios, population growth, and climate change. We decompose the combined effects into the roles of the individual components on the supply of riverine nitrogen for the entire US and eight coastal regions. We find that population growth is the most important driver of changes in coastal nitrogen flux. Energy policies play a minor role in offsetting the negative effects of population growth, although the effect varies by energy policy and region. The greatest population and policy effects are projected for the Gulf of Mexico. Given limited reductions in nitrogen emissions and deposition associated with energy policies, the net effect of policy and population changes is an increase in total nitrogen flux to all estuaries relative to the 2010 baseline. While population growth increases flux, and energy policies decrease flux in all regions, climate change can either increase or decrease flux depending on the region. That is because the relatively large individual effects of temperature and precipitation on watershed nitrogen processes work in opposing directions. The net result of the offsetting nature of individual climate processes varies in both magnitude and direction by coastal region. Further research is needed to sort out individual temperature and precipitation effects in different regions.
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Affiliation(s)
- Jhih-Shyang Shih
- Resources for the Future, 1616 P Street NW, Washington, DC 20036, United States of America.
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244, United States of America.
| | - Dallas Burtraw
- Resources for the Future, 1616 P Street NW, Washington, DC 20036, United States of America.
| | - Huizhong Shen
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States of America.
| | | | - Amelia Keyes
- Resources for the Future, 1616 P Street NW, Washington, DC 20036, United States of America.
| | - Kathy Fallon Lambert
- Center for Climate, Health and the Global Environment, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA 02215, United States of America.
| | - Yilin Chen
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States of America.
| | - Armstead G Russell
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States of America.
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13
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Bishop GA. On-Road NO x Emissions Evaluation of the Repair Effectiveness for Recalled Volkswagen Group Light-Duty Diesel Vehicles in the United States. Environ Sci Technol 2021; 55:16581-16585. [PMID: 34881873 DOI: 10.1021/acs.est.1c06826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The admission by the Volkswagen Group in the fall of 2015 that they had duped the United States new vehicle emissions certification testing resulted in perhaps the most expensive violation of U.S. environmental vehicle emission regulations in its history. As part of the subsequent recall of more than 500 000 vehicles in the U.S., owners could sell their vehicles back to the companies or have them repaired. We have used a number of large on-road emission measurement data sets that were routinely collected before and after the recall to evaluate the fuel specific NOx emissions benefit for the vehicles that were repaired and remained in service. We found that on-road fuel specific NOx emissions were reduced by 83% from the prerepair group. The reductions increased to 91% if we only compare with vehicles that were fully repaired. NO2 emissions were dramatically reduced by an even larger percentage >95%. We find that the repairs resulted in fuel specific NOx emissions that are comparable or slightly lower than in-use light and medium-duty diesel trucks measured in Denver in 2020 indicating the repairs were a success.
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Affiliation(s)
- Gary A Bishop
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
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14
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Zare A, Stevanovic S, Jafari M, Verma P, Babaie M, Yang L, Rahman MM, Ristovski ZD, Brown RJ, Bodisco TA. Analysis of cold-start NO 2 and NOx emissions, and the NO 2/NOx ratio in a diesel engine powered with different diesel-biodiesel blends. Environ Pollut 2021; 290:118052. [PMID: 34479164 DOI: 10.1016/j.envpol.2021.118052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/27/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
In the transportation sector, the share of biofuels such as biodiesel is increasing and it is known that such fuels significantly affect NOx emissions. In addition to NOx emission from diesel engines, which is a significant challenge to vehicle manufacturers in the most recent emissions regulation (Euro 6.2), this study investigates NO2 which is a toxic emission that is currently unregulated but is a focus to be regulated in the next regulation (Euro 7). This manuscript studies how the increasing share of biofuels affects the NO2, NOx, and NO2/NOx ratio during cold-start (in which the after-treatment systems are not well-effective and mostly happens in urban areas). Using a turbocharged cummins diesel engine (with common-rail system) fueled with diesel and biofuel derived from coconut (10 and 20% blending ratio), this study divides the engine warm-up period into 7 stages and investigates official cold- and hot-operation periods in addition to some intermediate stages that are not defined as cold in the regulation and also cannot be considered as hot-operation. Engine coolant, lubricating oil and exhaust temperatures, injection timing, cylinder pressure, and rate of heat release data were used to explain the observed trends. Results showed that cold-operation NOx, NO2, and NO2/NOx ratio were 31-60%, 1.14-2.42 times, and 3-8% higher than the hot-operation, respectively. In most stages, NO2 and the NO2/NOx ratio with diesel had the lowest value and they increased with an increase of biofuel in the blend. An injection strategy change significantly shifted the in-cylinder pressure and heat release diagrams, aligned with the sudden NOx drop during the engine warm-up. The adverse effect of cold-operation on NOx emissions increased with increasing biofuel share.
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Affiliation(s)
- Ali Zare
- School of Engineering, Deakin University, VIC, 3216, Australia.
| | | | - Mohammad Jafari
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia; International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), QLD, 4000, Australia
| | - Puneet Verma
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia; International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), QLD, 4000, Australia
| | - Meisam Babaie
- School of Computing, Science and Engineering (CSE), University of Salford, Manchester M5 4WT, Salford, United Kingdom
| | - Liping Yang
- Institute of Power and Energy Engineering, Harbin Engineering University, No. 145-1, Nantong Street, Nangang District, Harbin, 150001, China
| | - M M Rahman
- School of Mechanical Aerospace and Automotive Engineering, Coventry University, Coventry, CV1 2JH, UK
| | - Zoran D Ristovski
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia; International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), QLD, 4000, Australia
| | - Richard J Brown
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia
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15
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Tan Y, Yoon S, Ruehl CR, Herner J, Henderick P, Montes T, Latt J, Lee A, Florea E, Lemieux S, Robertson W, Hu S, Huai T. Assessment of In-Use NOx Emissions from Heavy-Duty Diesel Vehicles Equipped with Selective Catalytic Reduction Systems. Environ Sci Technol 2021; 55:13657-13665. [PMID: 34591445 DOI: 10.1021/acs.est.1c03042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This work evaluated the nitrogen oxide (NOx) emissions of 277 heavy-duty diesel vehicles (HDDVs) from three portable emission measurement system testing programs. HDDVs in these programs were properly maintained before emission testing, so the malfunction indicator lamp (MIL) was not illuminated. NOx emissions of some HDDVs were significantly higher than the certification standard even during hot operations where exhaust temperature was ideal for selective catalytic reduction to reduce NOx. For engines certified to the 0.20 g/bhp-hr NOx standard, hot operation NOx emissions increased with engine age at 0.081 ± 0.016 g/bhp-hr per year. The correlation between emissions and mileage was weak because six trucks showed extraordinarily high apparent emission increase rates reaching several multiples of the standard within the first 15,000 miles of operation. The overall annual increase in NOx emissions for the HDDVs in this study was two-thirds of what was observed in real-world emissions for HDDVs at the Caldecott Tunnel over the past decade. The vehicles at the Caldecott Tunnel would include those without proper maintenance, and the inclusion of these vehicles possibly explains the difference in the rate of emission increase. The results suggest that HDDVs need robust strategies to better control in-use NOx emissions.
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Affiliation(s)
- Yi Tan
- California Air Resources Board, 1001 I Street, Sacramento, California 95814, United States
| | - Seungju Yoon
- California Air Resources Board, 1001 I Street, Sacramento, California 95814, United States
| | - Chris R Ruehl
- California Air Resources Board, 1001 I Street, Sacramento, California 95814, United States
| | - Jorn Herner
- California Air Resources Board, 1001 I Street, Sacramento, California 95814, United States
| | - Paul Henderick
- California Air Resources Board, 9500 Telstar Avenue, Ste. #2, El Monte, California 91731, United States
| | - Tom Montes
- California Air Resources Board, 9500 Telstar Avenue, Ste. #2, El Monte, California 91731, United States
| | - Jenna Latt
- California Air Resources Board, 9500 Telstar Avenue, Ste. #2, El Monte, California 91731, United States
| | - Abraham Lee
- California Air Resources Board, 9500 Telstar Avenue, Ste. #2, El Monte, California 91731, United States
| | - Elena Florea
- California Air Resources Board, 9500 Telstar Avenue, Ste. #2, El Monte, California 91731, United States
| | - Sharon Lemieux
- California Air Resources Board, 9500 Telstar Avenue, Ste. #2, El Monte, California 91731, United States
| | - William Robertson
- California Air Resources Board, 9500 Telstar Avenue, Ste. #2, El Monte, California 91731, United States
| | - Shaohua Hu
- California Air Resources Board, 8340 Ferguson Avenue, Sacramento, California 95828, United States
| | - Tao Huai
- California Air Resources Board, 8340 Ferguson Avenue, Sacramento, California 95828, United States
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16
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Zhang G, Yan H, Li T, Zhu Y, Zhou S, Feng Y, Zhou W. Relation analysis on emission control and economic cost of SCR system for marine diesels. Sci Total Environ 2021; 788:147856. [PMID: 34134387 DOI: 10.1016/j.scitotenv.2021.147856] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/04/2021] [Accepted: 05/14/2021] [Indexed: 06/12/2023]
Abstract
In order to meet the IMO Tier III emissions regulations and reduce environmental pollution, many ocean-going vessels have installed the marine SCR system to reduce NOx emissions. However, the investment cost and operation cost of the marine SCR system, as well as the factors affecting the SCR cost are still the problems that need to be studied. In this paper, MAN S46 diesel engine matched SCR system was taken as the research object, and a cost calculation model of Marine SCR system based on cost analysis method has been proposed. The relationship between SCR system cost and some factors such as unit capacity, unit running time and inlet NOx concentration have been analyzed. The research we have done suggests that operating time, NOx inlet concentration, and emission limits are the three main important factors in the operating cost of an SCR system. Among the various secondary costs of operating costs, the reducing agent cost, fuel increase cost, and indirect annual cost account for 60%, 24%, and 7%, respectively. Moreover, the results suggest that the unit denitration cost of the matched SCR system is highly affected by the power of the diesel engine and annual running time. This study demonstrated clearly the relationship between emission control and economic cost of SCR system for marine diesels and was expected to provide a theoretical basis for sustainable development in marine environmental protection policies.
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Affiliation(s)
- Guangwei Zhang
- College of Power and Energy Engineering, Harbin Engineering University, China; China Shipbuilding Industry Corporation Diesel Engine Co., Ltd, Qingdao, China
| | - Haoyu Yan
- College of Power and Energy Engineering, Harbin Engineering University, China
| | - Tinghui Li
- College of Power and Energy Engineering, Harbin Engineering University, China.
| | - Yuanqing Zhu
- College of Power and Energy Engineering, Harbin Engineering University, China.
| | - Song Zhou
- College of Power and Energy Engineering, Harbin Engineering University, China
| | - Yongming Feng
- College of Power and Energy Engineering, Harbin Engineering University, China
| | - Weihao Zhou
- College of Power and Energy Engineering, Harbin Engineering University, China
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17
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McCaffery C, Zhu H, Tang T, Li C, Karavalakis G, Cao S, Oshinuga A, Burnette A, Johnson KC, Durbin TD. Real-world NOx emissions from heavy-duty diesel, natural gas, and diesel hybrid electric vehicles of different vocations on California roadways. Sci Total Environ 2021; 784:147224. [PMID: 33905931 DOI: 10.1016/j.scitotenv.2021.147224] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 05/28/2023]
Abstract
This study assessed the real-world nitrogen oxide (NOx) emissions from 50 heavy-duty vehicles of different vocations and engine technologies using portable emissions measurement systems (PEMS). This is one of the most comprehensive in-use emissions studies conducted to date, which played a key role in the development of CARB's (California Air Recourses Board) updated EMission FACtor (EMFAC) model, especially for natural gas vehicles. In-use emissions testing was performed on school and transit buses, refuse haulers, goods movement vehicles, and delivery vehicles while were driven over their normal operating routes in the South Coast Air Basin. Engine technologies included diesel engines with and without selective catalytic reduction (SCR) systems, compressed natural gas (CNG) engines and liquified petroleum gas (LPG) engines, and SCR-equipped diesel hybrid electric vehicles. For most vehicles, the in-use NOx emissions were higher than the certification standards for the engine. Diesel vehicles generally showed higher brake-specific NOx emissions compared to the CNG vehicles. NOx emissions were strongly dependent on the SCR temperature, with SCR temperatures below 200 °C resulting in elevate brake-specific NOx. The 0.02 g/bhp-hr certified CNG vehicles showed the largest reductions in NOx emissions. The diesel hybrid electric vehicles showed important distance-specific NOx benefits compared to the conventional diesel vehicles, but higher emissions compared to the CNG and LPG vehicles. Overall, average NOx reductions were 75%, 94%, 65%, 79%, respectively, for the 0.2 CNG, 0.02 CNG, diesel hybrid electric, and LPG vehicles compared to diesel vehicles, due in part to some diesel vehicles with particularly high emissions, indicating that the widespread implementation of advanced technology and alternative fuel vehicles could provide important NOx reductions and a path for meeting air quality targets in California and elsewhere.
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Affiliation(s)
- Cavan McCaffery
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA
| | - Hanwei Zhu
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Tianbo Tang
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Chengguo Li
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA
| | - Georgios Karavalakis
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA.
| | - Sam Cao
- South Coast Air Quality Management District, 21865 Copley Dr, Diamond Bar, CA 91765, USA
| | - Adewale Oshinuga
- South Coast Air Quality Management District, 21865 Copley Dr, Diamond Bar, CA 91765, USA
| | | | - Kent C Johnson
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Thomas D Durbin
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA.
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18
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Lee Y, Lee S, Lee S, Choi H, Min K. Characteristics of NOx emission of light-duty diesel vehicle with LNT and SCR system by season and RDE phase. Sci Total Environ 2021; 782:146750. [PMID: 33839657 DOI: 10.1016/j.scitotenv.2021.146750] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/06/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
As the regulations on vehicle emissions have become more stringent internationally and real-driving emissions (RDE) have been established, the on-road characteristics of emissions have gained importance in vehicle research and development. The results of the fuel consumption levels and emissions from on-road tests are affected by many factors, such as driving conditions, routes and environmental conditions. Therefore, more research and analysis are needed for the effects of environmental factors and driving conditions according to RDE phase on the NOx emissions. In this study, RDE tests were conducted by season to analyze the on-road NOx emission characteristics of lean NOx trap (LNT)- and selective catalytic reduction (SCR)-equipped diesel vehicles corresponding to the Euro 6b regulation prior to the application of the RDE regulation. The purpose of this study is to analyze the effects of seasonal factors and phases of the RDE routes on the NOx emission and NOx conversion efficiency of catalyst. In spring/autumn and summer, the engine-out and tail-pipe NOx emissions were higher 1.3-5.9 times for vehicle A and 1.3-28.4 times for vehicle B in the urban phase than in other phases. In the urban phase, the engine bay temperature was probable to rise owing to frequent stops and low-speed driving, leading to a high intake air temperature, which causes excessive NOx emission, particularly in summer. The average air filter temperature in urban phase was 11-15 °C higher than the environment temperature for vehicle A. The NOx conversion efficiency of the LNT was highest at 54.1% on motorway and the efficiency was dependent on the phase of the test route. The NOx conversion efficiency of the SCR, which is dependent on the catalyst temperature, was highest at 98.7% in spring motorway and the efficiency was affected by the combined factors of season and phases.
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Affiliation(s)
- Yongjoo Lee
- Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Seungil Lee
- Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Seunghyun Lee
- Hyundai Motor Company, Hwasung-si, Gyeonggi-Do, 455-963, Republic of Korea
| | - Hoimyung Choi
- Department of Mechanical Engineering, Gachon University, Gyeonggi 13120, Republic of Korea.
| | - Kyoungdoug Min
- Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
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19
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Deng J, Wang X, Wei Z, Wang L, Wang C, Chen Z. A review of NOx and SOx emission reduction technologies for marine diesel engines and the potential evaluation of liquefied natural gas fuelled vessels. Sci Total Environ 2021; 766:144319. [PMID: 33421776 DOI: 10.1016/j.scitotenv.2020.144319] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/05/2020] [Accepted: 12/05/2020] [Indexed: 05/25/2023]
Abstract
Due to intensive marine activities and the use of low-quality fuel oils, the marine transport accounts for a considerable part of air pollution in the transportation sector. Although ships provide the convenient transportation, they exhaust a large number of hazardous pollutants, especially nitrogen oxides (NOx) and sulfur oxides (SOx), which have a significant side effect on environment and human health. To alleviate the impact of global shipping on the environment, international maritime organization established the more stringent emission regulations from Tier I to Tier III in order to reduce emissions from ships. As a result, various emission reduction technologies need to be developed in order to meet more stringent regulations in the future and reduce the pollutant emissions. Under this background, it is indispensable to examine the existing emission reduction technologies when exploring another possible method to reduce the pollutant emissions. Based on a significant number of related literatures, it is general to utilize the marine alternative fuels to reduce the pollutant emissions. Especially, liquid natural gas (LNG) is considered to be one of the most promising marine alternative fuels due to its economy and environmentally friendly features. This review thus aims to summarize the different emission reduction technologies of marine diesel engines through three reduction paths of fuel optimization, pre-combustion control and exhaust after-treatment. Furthermore, the utilization of LNG in the marine diesel engines are evaluated comprehensively from three aspects of environmental protection, energy structure and economic benefits. At the end, some suggestions on the future research are given based on the extensive review on the state-of-the-art literature.
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Affiliation(s)
- Jiaojun Deng
- School of Mechanics and Electronics Engineering, Hainan University, Haikou, PR China
| | - Xiaochen Wang
- School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, PR China
| | - Zhilong Wei
- School of Mechanics and Electronics Engineering, Hainan University, Haikou, PR China
| | - Li Wang
- School of Mechanics and Electronics Engineering, Hainan University, Haikou, PR China
| | - Chenyu Wang
- School of Mechanics and Electronics Engineering, Hainan University, Haikou, PR China
| | - Zhenbin Chen
- School of Mechanics and Electronics Engineering, Hainan University, Haikou, PR China.
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20
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Goldberg DL, Anenberg SC, Kerr GH, Mohegh A, Lu Z, Streets DG. TROPOMI NO 2 in the United States: A Detailed Look at the Annual Averages, Weekly Cycles, Effects of Temperature, and Correlation With Surface NO 2 Concentrations. Earths Future 2021; 9:e2020EF001665. [PMID: 33869651 PMCID: PMC8047911 DOI: 10.1029/2020ef001665] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 01/10/2021] [Accepted: 02/10/2021] [Indexed: 05/27/2023]
Abstract
Observing the spatial heterogeneities of NO2 air pollution is an important first step in quantifying NOX emissions and exposures. This study investigates the capabilities of the Tropospheric Monitoring Instrument (TROPOMI) in observing the spatial and temporal patterns of NO2 pollution in the continental United States. The unprecedented sensitivity of the sensor can differentiate the fine-scale spatial heterogeneities in urban areas, such as emissions related to airport/shipping operations and high traffic, and the relatively small emission sources in rural areas, such as power plants and mining operations. We then examine NO2 columns by day-of-the-week and find that Saturday and Sunday concentrations are 16% and 24% lower respectively, than during weekdays. We also analyze the correlation of daily maximum 2-m temperatures and NO2 column amounts and find that NO2 is larger on the hottest days (>32°C) as compared to warm days (26°C-32°C), which is in contrast to a general decrease in NO2 with increasing temperature at moderate temperatures. Finally, we demonstrate that a linear regression fit of 2019 annual TROPOMI NO2 data to annual surface-level concentrations yields relatively strong correlation (R 2 = 0.66). These new developments make TROPOMI NO2 satellite data advantageous for policymakers and public health officials, who request information at high spatial resolution and short timescales, in order to assess, devise, and evaluate regulations.
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Affiliation(s)
- Daniel L. Goldberg
- Department of Environmental and Occupational HealthGeorge Washington UniversityWashingtonDCUSA
- Energy Systems DivisionArgonne National LaboratoryArgonneILUSA
| | - Susan C. Anenberg
- Department of Environmental and Occupational HealthGeorge Washington UniversityWashingtonDCUSA
| | - Gaige Hunter Kerr
- Department of Environmental and Occupational HealthGeorge Washington UniversityWashingtonDCUSA
| | - Arash Mohegh
- Department of Environmental and Occupational HealthGeorge Washington UniversityWashingtonDCUSA
| | - Zifeng Lu
- Energy Systems DivisionArgonne National LaboratoryArgonneILUSA
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21
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Vedagiri P, Martin LJ, Varuvel EG. Characterization of urea SCR using Taguchi technique and computational methods. Environ Sci Pollut Res Int 2021; 28:11988-11999. [PMID: 32306257 DOI: 10.1007/s11356-020-08743-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Use of biodiesel in diesel engine helps to reduce HC, CO, and smoke emissions due to their enormous oxygen content, whereas NOx emissions formed by Zeldovich mechanism shoot up. Implementation of Bharat Stage (BS) VI by April 2020 in India has created extreme pressure on automobile manufacturers to include after treatment technology in their systems. Selective catalytic reduction (SCR), a NOx control technology, is operated using aqueous urea solution as the reductant. There are several parameters that need to be monitored to enhance the NOx conversion efficiency of SCR retrofit. The uniformity index of ammonia, which determines the conversion efficiency, is greatly influenced by parameters like exhaust gas temperature, injection angle, injector position, mass flow rate, and SCR geometry. This paper considers two types of SCR design, namely SCR with and without mixer design and their impact on NOx reduction. The effect of mass flow rate on urea conversion in SCR design without mixer is 27%, but the impact is reduced greatly in SCR design with mixer with less than 2% variation. The UI resulting from different cases ranges from 0.59 to 0.83. Using Taguchi technique and CFD tool, the impact of parameters on both the SCR designs has been investigated and the optimum SCR design is reported.
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Affiliation(s)
- Praveena Vedagiri
- Department of Mechanical Engineering, SRM University, Kattankulathur, 603203, India.
| | - Leenus Jesu Martin
- Department of Automobile Engineering, SRM University, Kattankulathur, 603203, India
| | - Edwin Geo Varuvel
- Department of Automobile Engineering, SRM University, Kattankulathur, 603203, India
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22
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Abstract
A thorough understanding of the drivers that affect the emission levels from electricity generation, support sound design and the implementation of further emission reduction goals are presented here. For instance, New York State has already committed a transition to 100% clean energy by 2040. This paper identifies the relationships among driving factors and the changes in emissions levels between 1990 and 2050 using the logarithmic mean divisia index analysis. The analysis relies on historical data and outputs from techno-economic-energy system modeling to elude future power sector pathways. Three scenarios, including a business-as-usual scenario and two policy scenarios, explore the changes in utility structure, efficiency, fuel type, generation, and emission factors, considering the non-fossil-based technology options and air regulations. We present retrospective and prospective analysis of carbon dioxide, sulfur dioxide, nitrogen oxide emissions for the New York State’s power sector. Based on our findings, although the intensity varies by period and emission type, in aggregate, fossil fuel mix change can be defined as the main contributor to reduce emissions. Electricity generation level variations and technical efficiency have relatively smaller impacts. We also observe that increased emissions due to nuclear phase-out will be avoided by the onshore and offshore wind with a lower fraction met by solar until 2050.
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Affiliation(s)
- Mine Isik
- Correspondence: ; Tel.: +1-919-541-4965
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23
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Mohammadi M, Neshat E. Accurate prediction of NOx emissions from diesel engines considering in-cylinder ion current. Environ Pollut 2020; 266:115347. [PMID: 32814177 DOI: 10.1016/j.envpol.2020.115347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/10/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
The main purpose of current study is accurate prediction of NOx emissions from diesel engines considering in-cylinder ion current. To reach this goal, a validated thermodynamic multi-zone model was used. A modified chemical kinetics mechanism of diesel fuel oxidation was used too. A chemical kinetics mechanism of NOX formation including 103 reactions was added to the main mechanism. A set of ions and ionic reactions was added to the developed chemical kinetics mechanism and finally a modified chemical kinetics mechanism with 445 reactions and 100 species was formed. The developed mechanism was coupled to the multi-zone model and a diesel engine was simulated. The importance of Zeldovich mechanism, prompt mechanism, N2O mechanism and NNH mechanism were investigated. The progress rates of reactions were calculated and important reactions were identified. The results show that the oxygenated ions, NO+, O+ and O2+, has more effects on NO production than other ions. The prompt mechanism plays an important role in predicting the ion current inside the chamber. Because this mechanism has reactions that can lead to CH production. The CH radicals produced by this mechanism can be employed by basic ionic reactions and lead to ion production. The results show that using NOx related ionic reactions results in accurate prediction of engine exhaust NOx.
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Affiliation(s)
- Milad Mohammadi
- Faculty of Mechanical Engineering, Sahand University of Technology, Sahand New Town, Tabriz, Iran
| | - Elaheh Neshat
- Faculty of Mechanical Engineering, Sahand University of Technology, Sahand New Town, Tabriz, Iran.
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24
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Goldberg DL, Anenberg SC, Griffin D, McLinden CA, Lu Z, Streets DG. Disentangling the Impact of the COVID-19 Lockdowns on Urban NO 2 From Natural Variability. Geophys Res Lett 2020; 47:e2020GL089269. [PMID: 32904906 PMCID: PMC7461033 DOI: 10.1029/2020gl089269] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/30/2020] [Accepted: 08/03/2020] [Indexed: 05/20/2023]
Abstract
TROPOMI satellite data show substantial drops in nitrogen dioxide (NO2) during COVID-19 physical distancing. To attribute NO2 changes to NO x emissions changes over short timescales, one must account for meteorology. We find that meteorological patterns were especially favorable for low NO2 in much of the United States in spring 2020, complicating comparisons with spring 2019. Meteorological variations between years can cause column NO2 differences of ~15% over monthly timescales. After accounting for solar angle and meteorological considerations, we calculate that NO2 drops ranged between 9.2% and 43.4% among 20 cities in North America, with a median of 21.6%. Of the studied cities, largest NO2 drops (>30%) were in San Jose, Los Angeles, and Toronto, and smallest drops (<12%) were in Miami, Minneapolis, and Dallas. These normalized NO2 changes can be used to highlight locations with greater activity changes and better understand the sources contributing to adverse air quality in each city.
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Affiliation(s)
- Daniel L. Goldberg
- Department of Environmental and Occupational HealthGeorge Washington UniversityWashingtonDCUSA
- Energy Systems DivisionArgonne National LaboratoryLemontILUSA
| | - Susan C. Anenberg
- Department of Environmental and Occupational HealthGeorge Washington UniversityWashingtonDCUSA
| | - Debora Griffin
- Air Quality Research DivisionEnvironment and Climate Change Canada (ECCC)TorontoOntarioCanada
| | - Chris A. McLinden
- Air Quality Research DivisionEnvironment and Climate Change Canada (ECCC)TorontoOntarioCanada
| | - Zifeng Lu
- Energy Systems DivisionArgonne National LaboratoryLemontILUSA
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25
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Vedagiri P, Martin LJ, Varuvel EG, Subramanian T. Experimental study on NO x reduction in a grapeseed oil biodiesel-fueled CI engine using nanoemulsions and SCR retrofitment. Environ Sci Pollut Res Int 2020; 27:29703-29716. [PMID: 31410826 DOI: 10.1007/s11356-019-06097-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Stringent emission norms impose challenges to original equipment manufacturer (OEM) in reducing diesel engine emissions. Implementing renewable fuels as alternative energy sources in diesel engines leads to increased emission levels particularly NOx. In this work, performance, combustion, and emission parameters from a diesel engine powered with grapeseed oil biodiesel (GSBD) was investigated. Nano additive emulsions of cerium oxide (CeO2) and zinc oxide (ZnO) at 100 ppm each were added to grapeseed oil biodiesel. To enhance the NOx reduction task further, an advanced technology called selective catalytic reduction (SCR) system was used. With easy availability of aqueous urea, careful injection, and distribution of the reductant solution, a paradigm change was brought about in NOx reduction technology. The experiments were carried out with and without SCR for better understanding and investigation. The percentage reduction of NOx emission by adding cerium oxide and zinc oxide emulsion blends were 4.19% and 13.13%, respectively. The overall reduction in NOx emission were 74.16% and 80.06% with SCR for cerium oxide and zinc oxide emulsion blends. The research conclusions make grapeseed oil biodiesel conceivable as an effective alternate fuel for diesel engines without any engine modifications.
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Affiliation(s)
- Praveena Vedagiri
- Department of Mechanical Engineering, SRM University, Kattankulathur, 603203, India.
| | - Leenus Jesu Martin
- Department of Automobile Engineering, SRM University, Kattankulathur, 603203, India
| | - Edwin Geo Varuvel
- Department of Automobile Engineering, SRM University, Kattankulathur, 603203, India
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26
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Li X, Zeng L, Liu H, Song M, Liu W, Han H, Zhang S, Chen Z, Li Z. Numerical simulation investigations into the influence of the mass ratio of pulverized-coal in fuel-rich flow to that in fuel-lean flow on the combustion and NO x generation characteristics of a 600-MW down-fired boiler. Environ Sci Pollut Res Int 2020; 27:16900-16915. [PMID: 32144700 DOI: 10.1007/s11356-020-08275-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
Numerical simulations were conducted to study the effects of the pulverized-coal bias distribution in the primary air on the coal combustion and NOx generation characteristics of a 600-MW down-fired boiler with multiple-injection and multiple-staging combustion technology. The total pulverized-coal in the primary air was kept constant, and the ratio of the pulverized-coal mass flux in the fuel-rich coal/air flow to the total pulverized-coal mass flux (RPR) was set as 60%, 70%, 80%, and 90%. By changing the RPR, the excess air coefficient of the fuel-rich flow was adjusted from 0.700 to 0.467. It was found that numerical simulation results were almost in agreement with cold modeling and in situ experimental results respectively, including the flow fields in the lower furnace at the RPR of 80% and the heating processes for the fuel-rich coal/air flow at the RPR of 90%, which verified the rationality of the numerical model and the grid. The simulation results indicated that the change of RPR has little effect on the symmetry of the flow field in the furnace. With the increase of the RPR from 60 to 90%: (1) the maximum airflow declination angle near the tertiary air slot decreased from 71 to 66°, which indicates that the downward airflow penetration depth gradually decreased; (2) the ignition distance of the fuel-rich coal/air flow decreased from 1.2 to 0.9 m, and the high-temperature area in the furnace hopper decreased and the position gradually moved away from the hopper water walls; (3) the oxygen consumption rate at the initial combustion stage constantly accelerated, and the fuel NOx generation rate under the fuel-rich flow nozzle increased first and then decreased; (4) the NOx emissions at the furnace exit dropped from 778 to 662 mg/m3 at 6% O2, and the carbon in the fly ash decreased from 5.87 to 5.52%. Increasing the RPR reasonably controlled the excess air coefficient of the fuel-rich flow, and realized the high-efficiency combustion in the furnace and the reduction of NOx emissions simultaneously.
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Affiliation(s)
- Xiaoguang Li
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
| | - Lingyan Zeng
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China.
| | - Hongye Liu
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
| | - Minhang Song
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
| | - Wenjie Liu
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
| | - Hui Han
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
| | - Shaofeng Zhang
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
| | - Zhichao Chen
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
| | - Zhengqi Li
- School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, People's Republic of China
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McCaffery C, Zhu H, Li C, Durbin TD, Johnson KC, Jung H, Brezny R, Geller M, Karavalakis G. On-road gaseous and particulate emissions from GDI vehicles with and without gasoline particulate filters (GPFs) using portable emissions measurement systems (PEMS). Sci Total Environ 2020; 710:136366. [PMID: 31923692 DOI: 10.1016/j.scitotenv.2019.136366] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/14/2019] [Accepted: 12/25/2019] [Indexed: 06/10/2023]
Abstract
This study assessed the on-road gaseous and particulate emissions from three current technology gasoline direct injection (GDI) vehicles using portable emissions measurement systems (PEMS). Two vehicles were also retrofitted with catalyzed gasoline particulate filters (GPFs). All vehicles were exercised over four routes with different topological and environmental characteristics, representing urban, rural, highway, and high-altitude driving conditions. The results showed strong reductions in particulate mass (PM), soot mass, and particle number emissions with the use of GPFs. Particle emissions were found to be highest during urban and high-altitude driving compared to highway driving. The reduction efficiency of the GPFs ranged from 44% to 99% for overall soot mass emissions. Similar efficiencies were found for particle number and PM mass emissions. In most cases, nitrogen oxide (NOx) emissions showed improvements with the catalyzed GPFs in the underfloor position with the additional catalytic volume. No significant differences were seen in carbon dioxide (CO2) and carbon monoxide (CO) emissions with the vehicles retrofitted with GPFs.
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Affiliation(s)
- Cavan McCaffery
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Mechanical Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Hanwei Zhu
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Chengguo Li
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA
| | - Thomas D Durbin
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Kent C Johnson
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Heejung Jung
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Mechanical Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA
| | - Rasto Brezny
- Manufacturers of Emission Controls Association, 2200 Wilson Boulevard, Suite 310, Arlington, VA 22201, USA
| | - Michael Geller
- Manufacturers of Emission Controls Association, 2200 Wilson Boulevard, Suite 310, Arlington, VA 22201, USA
| | - Georgios Karavalakis
- University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA.
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28
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Liu J, Luo X, Yao S, Li Q, Wang W. Influence of flue gas recirculation on the performance of incinerator-waste heat boiler and NOx emission in a 500 t/d waste-to-energy plant. Waste Manag 2020; 105:450-456. [PMID: 32135466 DOI: 10.1016/j.wasman.2020.02.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/19/2020] [Accepted: 02/26/2020] [Indexed: 06/10/2023]
Abstract
The flue gas composition and the flue gas temperature at outlet of the economizer were tested, and the influence of flue gas recirculation (FGR) on the efficiency of the incinerator-waste heat boiler and NOx emission in a waste incineration power plant with a waste disposal capacity of 500 t/d was explored experimentally. The results indicate that the largest proportion of the total heat loss is the exhaust heat loss under different loads, and the next is the heat loss of slag. Within the test range, the efficiency of the incinerator-waste heat boiler increases from 80.26% to 80.42% as the ratio of the recirculating flue gas increases from 0 to 16.43%. The oxygen content in the flue gas and FGR have significant influence on NOx emissions. The NOx concentration at outlet of the economizer increases from 209.54 mg/m3 to 307.30 mg/m3, that is an increase of 46.65%, when the oxygen content at outlet of the economizer increases from 4.52% to 8.00%. Compared with the shutdown of FGR system, the NOx concentration at outlet of the economizer decreases from 209.54 mg/m3 to 126.15 mg/m3 when the FGR valve is fully opened. The results have important reference significance for the design of incinerator-waste heat boiler and the optimal operation of power plant.
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Affiliation(s)
- Jun Liu
- School of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450045, China.
| | - Xiaoyu Luo
- School of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450045, China
| | - Sheng Yao
- Xi'an Thermal Power Research Institute Co., Ltd, Suzhou Branch, Suzhou 215153, China
| | - Quangong Li
- School of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450045, China
| | - Weishu Wang
- School of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450045, China
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29
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Diao B, Ding L, Su P, Cheng J. The Spatial-Temporal Characteristics and Influential Factors of NOx Emissions in China: A Spatial Econometric Analysis. Int J Environ Res Public Health 2018; 15:E1405. [PMID: 29973509 DOI: 10.3390/ijerph15071405] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/25/2018] [Accepted: 06/28/2018] [Indexed: 11/25/2022]
Abstract
While the progress of China’s industrialization and urbanization has made great strides, atmospheric pollution has become the norm, with a wide range of influence and difficult governance. While many previous works on NOx pollution have been developed from the perspectives of natural science and technology, few studies have been conducted from social-economic points of view, and regional differences have not been given adequate attention in driving force models. This paper adopts China’s provincial panel data from 2006 to 2015, an extended STIRPAT (Stochastic Impacts by Regression on Population, Affluence and Technology) model, and spatial econometric models to investigate the socio-economic influential factors and spatial-temporal patterns of NOx emissions. According to the spatial correlation analysis results, the provincial NOx emission changes not only affected the provinces themselves, but also neighboring regions. Spatial econometric analysis shows that the spatial effect largely contributes to NOx emissions. The other explanatory variables all have positive impacts on NOx emissions, except for the vehicular indicator (which did not pass the significance test). As shown through the estimated consequences of direct and indirect effects, the indicators have significant positive effects on their own areas, and exacerbate NOx pollution. In terms of indirect effects, only three factors passed the significant test. An increase in gross domestic product (GDP) and energy consumption will exacerbate adjacent NOx pollution. Finally, a series of socio-economic measures and regional cooperation policies should be applied to improve the current air environment in China.
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30
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Suarez-Bertoa R, Astorga C. Impact of cold temperature on Euro 6 passenger car emissions. Environ Pollut 2018; 234:318-329. [PMID: 29190540 PMCID: PMC5817001 DOI: 10.1016/j.envpol.2017.10.096] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/25/2017] [Accepted: 10/25/2017] [Indexed: 05/19/2023]
Abstract
Hydrocarbons, CO, NOx, NH3, N2O, CO2 and particulate matter emissions affect air quality, global warming and human health. Transport sector is an important source of these pollutants and high pollution episodes are often experienced during the cold season. However, EU vehicle emissions regulation at cold ambient temperature only addresses hydrocarbons and CO vehicular emissions. For that reason, we have studied the impact that cold ambient temperatures have on Euro 6 diesel and spark ignition (including: gasoline, ethanol flex-fuel and hybrid vehicles) vehicle emissions using the World-harmonized Light-duty Test Cycle (WLTC) at -7 °C and 23 °C. Results indicate that when facing the WLTC at 23 °C the tested vehicles present emissions below the values set for type approval of Euro 6 vehicles (still using NEDC), with the exception of NOx emissions from diesel vehicles that were 2.3-6 times higher than Euro 6 standards. However, emissions disproportionally increased when vehicles were tested at cold ambient temperature (-7 °C). High solid particle number (SPN) emissions (>1 × 1011 # km-1) were measured from gasoline direct injection (GDI) vehicles and gasoline port fuel injection vehicles. However, only diesel and GDI SPN emissions are currently regulated. Results show the need for a new, technology independent, procedure that enables the authorities to assess pollutant emissions from vehicles at cold ambient temperatures. Harmful pollutant emissions from spark ignition and diesel vehicles are strongly and negatively affected by cold ambient temperatures. Only hydrocarbon, CO emissions are currently regulated at cold temperature. Therefore, it is of great importance to revise current EU winter vehicle emissions regulation.
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Affiliation(s)
- Ricardo Suarez-Bertoa
- European Commission Joint Research Centre, Directorate for Energy, Transport and Climate, Sustainable Transport Unit, 21027 Ispra, VA, Italy.
| | - Covadonga Astorga
- European Commission Joint Research Centre, Directorate for Energy, Transport and Climate, Sustainable Transport Unit, 21027 Ispra, VA, Italy.
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31
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Wu WL, Xue WB, Wang YL, Lei Y. [Application of Satellite Remote Sensing in NO x Emission Control]. Huan Jing Ke Xue 2017; 38:3998-4004. [PMID: 29965181 DOI: 10.13227/j.hjkx.201703172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tropospheric NO2 vertical column densities (VCDs) from ozone monitoring instrument(OMI) were analyzed to evaluate the decrease in NOx emissions during two special events, 70th anniversary of the end of World War Ⅱ in 2015 and the G20 summit in 2016. Results showed a positive correlation between NO2 VCDs and near ground NOx emissions and verified that the NOx emission control policy during "12th five-year plan" were remarkably effective, with a 24.98% drop in VCDs in five years. At the early stage of "13th five-year plan", in 2016, NO2 VCDs decreased by 3.18% year-on-year, showing a consistent drop in NOx.
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Affiliation(s)
- Wei-Ling Wu
- Chinese Academy for Environmental Planning, Beijing 100012, China
| | - Wen-Bo Xue
- Chinese Academy for Environmental Planning, Beijing 100012, China
| | - Yan-Li Wang
- Chinese Academy for Environmental Planning, Beijing 100012, China
| | - Yu Lei
- Chinese Academy for Environmental Planning, Beijing 100012, China
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