Papers by Keyword: NOx

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Authors: Zhi Juan Gao, Wei Ren Bao, Li Ping Chang, Jian Cheng Wang
Abstract: A Cu-SAPO-34/cordierite monolithic catalyst was prepared by in-situ hydrothermal method. The effects of ultrasonic treatment were mainly investigated during the preparing process. The removal of NOX was evaluated using a fixed-bed reactor. X-ray diffraction, scanning electron microscopy were used to characterize the samples showing that the crystallinity of Cu-SAPO-34 molecular sieve have increased after ultrasonic treatment. The Cu-SAPO-34/cordierite prepared by ultrasonic treatment showed higher de-NOx activity and stronger anti-aging property. NOx conversion could reach more than 80% between 440 and 560°C over the fresh Cu-SAPO-34/cordierite catalyst with ultrasonic treatment (600 W, 2 h) and the highest conversion was 86%, however, the highest conversion was only 76% over the Cu-SAPO-34/cordierite catalyst without ultrasonic treatment. After aging (treated for 15 h at 720 °C in the presence of 200 ppm SO2 and 10% vapor), NOx conversion reached more than 45% between 400 and 520 °C over the catalyst with ultrasonic treatment and the highest conversion was 57%, however, the highest conversion was only 43% over the catalyst without ultrasonic treatment. The XRD and SEM results indicated that the structure and morphology of Cu-SAPO-34/cordierite monolithic catalyst kept in good condition after aging.
Authors: Enis T. Turgut
Abstract: In this study a novel method is developed to identify the NOx emissions released from commercial aircraft during descent. In order to obtain EINOx the real flight data and ICAO emissions database are used. According to the results, statistically significant models are found and the NOx emissions produced from aircraft are calculated to be higher compared to those obtained by ICAO EINOx. Also, the effects of vertical profile, EGT and N1 are discussed. Overall, the minimum and maximum NOx emissions released from the descent of ten flights are calculated as 2.4 kg and 7.2 kg for model 3, with 1.5 kg and 5.4 kg for the baseline, respectively.
Authors: Yasir Niaz, Ji Ti Zhou
Abstract: The increased occurrence of smoggy days in major Pakistan cities is of major concern to the general public. This paper explores the major sources of pollutants total suspended particles and lead concentration, a key contributor to the smog in Faisalabad, one of the largest cities in Pakistan. Evidence indicates that the total suspended particles and lead concentration formed through NOx, SOx, NH3, VOCs, etc. have a strong impact on human health. As a result, air pollution control should not simply focus on controlling particulate emission, but should involve adopting an integrated multi pollutant control strategy. In addition to identifying the major sources of air pollution, this paper explores its impact on environmental and human health. The results also compare with the permissible limit of NEQS and USEPA standards. The study shows that TSP concentration 80% values within the permissible limits of ambient air quality according to the standards of USEPA and NEQS. In the samples, Lead concentration is higher than the USEPA and NEQS standards of ambient air quality 1.5μg/m3 and 2μg/m3 respectively. The research suggests that adequate government regulation, public awareness, regional collaboration and industrial compliance are keys to successfully controlling air pollution.
Authors: Song Zhou, Yan Liu, Jin Xi Zhou
Abstract: This paper introduces the impact on the marine environment caused by marine diesel engine exhaust pollution and the regulations made by IMO to control the marine diesel engine emissions. And it summarizes the main technical measures to reduce SOx, NOx and particulate matter emissions from the marine diesel. It also points that the combination application of various technologies will be the research direction to reduce the emission of marine diesel engine in the future.
Authors: Min Xiao, Hui Chen
Abstract: The KIVA-3V program was used to make numerical simulation for L21/31 type of medium-speed marine diesel engine about the NOx emissions and the affection of NOx changing process on different variable parameters under the Tier Ⅱstandard. On this basis, a discussion towards the NOx emission of the model fueling with dimethyl ether (DME) to meet the Tier Ⅲ standard is offered. The results show that reducing the intake temperature, load and speed, postponing the fuel injection timing and intake lag angle properly can decrease the NOx emissions within the limits of NOx in TierⅡ standard. Comparing the results of the numerical simulation of DME and diesel fuel, the NOx emission of the former one is 60.85% of the latter one, and the NOx emission of changing variable parameters on DME engine is 35.56% of the original type of diesel engine, very close to the Tier Ⅲ.
Authors: Bo Yan Xu, Hai Ying Tian, Jie Yang, De Zhi Sun, Shao Li Cai
Abstract: SNCR (Selective Non Catalytic Reduction) system is proposed, with 40% methylamine aqueous solution as reducing agent to reduce NOx in diesel exhaust gas. The effect of injection position and volume on the reduction efficiency through the test bench is systematically researched. A three-dimensional model of a full-sized diesel SNCR system generated by CFD software FIRE is used to investigate the reduction efficiency under different temperatures. The simulated results have a good agreement with the test results, and it can be used to optimize SNCR system. The results can indicate the practical application of this technology.
Authors: Xiao Mei Zhu, Bing Sun, Hong Duan Xie, Lian Zheng Zhang, Jia Ni Zhao
Abstract: The atmospheric-pressure microwave plasma can remove perfluorocompounds (PFCs) efficiently, which have long lifetime and serious global warming implications. However, associated gases such as NOx are produced in the abatement process of PFCs. In order to destroy PFCs and NOx pollutants, TiO2 catalyst is introduced into the abatement system. The effective TiO2 catalysts are prepared by a sol-gel method with the ratio of tetrabutyl titanate, ethanol, H2O and acetic acid = 1: 7: 1: 0.4. The abatement of CF4 and associated gas (NOx) is carried out with combined microwave plasma and TiO2 catalyst. The results show that the combined microwave plasma and catalyst abatement system can be successfully used to remove CF4 and NOx. The destruction and removal efficiency of CF4 and NOx were higher with the combined catalyst and plasma process than that with catalyst or plasma only.
Authors: Qian Wang, Ming Xing Zhou, Bao Yi Wang
Abstract: In order to fulfill future emission standards for middle and heavy-duty vehicles like state Ⅳ and Ⅴ, advanced measures on exhaust gas and engine functionality are required. Selective Catalytic Reduction (SCR) technology is the unique technology currently which can improve the emission and reduce fuel consumption simultaneously. Firstly the reductants and its chemical reactions, SCR system configurations and its working principle and urea dosing control strategy are introduced. Then tests are conducted on a diesel engine with SCR system at bench. The results of ESC cycle show that NOx emission is decreased by more than 67% with the open-loop control strategy. Additionally, the urea and fuel consumption and ammonia leakage have been compared and analyzed respectively, the experiment data indicates that the urea water solution consumption ratio is only 5.7% of fuel for this SCR system, while its average ammonia slip is below 5 ppm.
Authors: Xue Jun Hou, Peng Xiao
Abstract: With the increasingly prominent problem regarding rapid economy development and a gradually serious environmental pollution, the waste gas pollution processing have received significant attention. Z12V190 diesel engine for petroleum drilling has high fuel consumption and releases large amounts of harmful waste gas into the atmosphere to cause serious environmental pollution. In this work, the mainly harmful components of Z12V190 exhaust gas are analysed, the corresponding methods of purification and processing about Z12V190 exhaust gas pollution discussed. In order to purify treatment pollution, and ultimate to lay the foundation for pollution treatment, the process flows of the exhaust gas pollution processing are preliminary designed.
Authors: Qian Wang, Ping Qi, Xiao Jing Han, Ming Xing Zhou
Abstract: In this paper, the Urea-SCR system is first introduced; then change of the urea solution concentration under different temperatures with time lapsing is given. Meanwhile, conditions for the urea crystallization are analyzed and SCR converter adaptability is tested under high sulfur environment on engine test bench. As the efficiency of NOx conversion is not significantly reduced after aging and the activity of the catalyst is very little damaged by dense sulfur content in fuel, SCR catalyst is able to adapt to the application of high-sulfur-contained fuel environment in our country.
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