This paper describes possible ways of prediction of nitrogen oxides formation during combustion of hydrocarbon fuels. Mathematical model based on experimental data acquired from the testing facility has been developed. The model enables to predict--at a high probability measure--the extent of nitrogen oxides emissions. The mathematical model of nitrogen oxide formation relies on the application of simplified kinetic equations describing the formation of nitrogen oxides at so-called equivalent temperature. It is a semi-empirical model that comes out of experimental knowledge. An important role played by the burner design itself has been emphasized and therefore an important supplementary parameter of the model is the characteristic of the burner design. It has been established that there was a good agreement between experimental data and those calculated by the application of the model to various conditions marked out by different combustion parameters in the combustion chamber. The results obtained by application of the model respect the influence of parameters validated by industrial practice that control the formation of nitrogen oxides in the course of fuel combustion. Such parameters-first of all-tare the temperature in the combustion chamber and the concentration of the substances taking part in the reaction. By application of the model, it is possible to assess the consequence of, for example the surplus of combustion air, the increase of temperature of combustion air, the supply of inert gas, etc. on the nitrogen oxides emissions of the operating burner under evaluation. Efficient combining of experience and sophisticated approach together with importance of thus access for an improved design are shown.
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http://dx.doi.org/10.1016/s0956-053x(02)00028-4 | DOI Listing |
Sci Total Environ
January 2025
Institute of Environmental Assessment and Water Research, Spanish Research Council (IDÆA-CSIC), c/Jordi Girona 18-26, 08034 Barcelona, Spain.
The maritime transport sector poses significant air quality concerns, particularly in nearby cities. Ultrafine particles (UFP, diameter < 100 nm) are of particular concern due to their potential health impacts. This study measured particle number concentrations (PNC), size distributions (PNSD), and other pollutants including particulate matter (PM), nitrogen oxides (NO), black carbon (BC), sulfur dioxide (SO) and ozone (O), organic markers and trace elements at a major European harbor and an urban background (UB) location.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853.
Ammonia oxidizing archaea (AOA) are among the most abundant microorganisms on earth and are known to be a major source of nitrous oxide (NO) emissions, although biochemical origins of this NO remain unknown. Enzymological details of AOA nitrogen metabolism are broadly unavailable. We report the recombinant expression, purification, and characterization of a multicopper oxidase, Nmar_1354, from the AOA .
View Article and Find Full Text PDFJ Cell Mol Med
January 2025
Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine and Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.
The pathogenesis of chronic thromboembolic pulmonary hypertension may be multifactorial and requires further studies. We explored alterations in pulmonary artery endothelial cells under the hypoxic and elevated interleukin-17 conditions that are commonly present in patients with chronic thromboembolic pulmonary hypertension. We measured the serum interleukin-17 levels in 10 chronic thromboembolic pulmonary hypertension patients and 10 healthy control persons.
View Article and Find Full Text PDFGlob Chang Biol
January 2025
Department of Environmental and Biological Sciences, Faculty of Science, Forestry and Technology, University of Eastern Finland, Kuopio, Finland.
Primary and secondary atmospheric pollutants, including carbon monoxide (CO), carbon dioxide (CO), nitrogen oxides (NO), ozone (O), sulphur dioxide (SO) and particulate matter (PM/PM) with associated heavy metals (HMs) and micro- and nanoplastics (MPs/NPs), have the potential to influence and alter interspecific interactions involving insects that are responsible for providing essential ecosystem services (ESs). Given that insects rely on olfactory cues for vital processes such as locating mates, food sources and oviposition sites, volatile organic compounds (VOCs) are of paramount importance in interactions involving insects. While gaseous pollutants reduce the lifespan of individual compounds that act as olfactory cues, gaseous and particulate pollutants can alter their biosynthesis and emission and exert a direct effect on the olfactory system of insects.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran.
In this study, a series of experiments are done to analyze the effect of bluff body geometry on the NO reduction of a natural gas-air stratified swirl burner. The stratified burner of Cambridge University is chosen to study the mentioned geometrical effect, and the geometry modification of bluff body is used as a simple method for NO reduction, which can be easily applied to the systems using these burners, including gas turbines. The bluff body geometrical change to an annular bluff body is inspired by the fact that the areas in which the edge of the bluff body is in contact with the unburned flow have lower temperatures, which can drastically affect combustion parameters, especially emissions.
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