{"title":"Numerical investigation of NOx emission characteristics in air-staged combustion system fueled by premixed ammonia/methane","authors":"","doi":"10.1016/j.joei.2024.101857","DOIUrl":null,"url":null,"abstract":"<div><div>For the purpose of achieving global CO<sub>2</sub> reduction, decarbonization at the source of fuels is a practical approach. The transition phase of blending fossil fuels with carbon-free fuels for combustion is a hot topic in the current carbon emission reduction process. In order to achieve efficient and low-pollution combustion of NH<sub>3</sub>/CH<sub>4</sub>, the combustion and emission characteristics of NH<sub>3</sub>/CH<sub>4</sub> under single-stage and air-staged combustion methods were numerically investigated in this work. The emissions were compared for different equivalence ratios and different ammonia content conditions. Rate of production (ROP) and sensitivity analysis were performed for NO<sub>x</sub>, and the reaction path of NH<sub>3</sub>/CH<sub>4</sub> was analyzed. The results indicate that the C-N interaction of the NH<sub>3</sub>/CH<sub>4</sub> mixed combustion process is not significant and turns weaker in the lean flames. HNO intermediate is an important specie for NO generation, and HCN together with HCO intermediate, are essential species for CO generation. NH<sub>2</sub> and NH almost dominate the promotion and inhibition of NO generation. Given the contrasting NO<sub>x</sub> and CO emission behavior of NH<sub>3</sub>/CH<sub>4</sub> in rich and lean flames, the single-stage combustion approach is not suitable. Air-staged combustion achieves both, ensuring the complete burning of NH<sub>3</sub> and CH<sub>4</sub> while reducing NO<sub>x</sub> and CO emissions. Moreover, the results suggest that <em>Φ</em><sub>pri</sub> = 1.2/<em>Φ</em><sub>total</sub> = 0.6 is the optimal NH<sub>3</sub>/CH<sub>4</sub> combustion staging method for controlling NO<sub>x</sub> emissions.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":null,"pages":null},"PeriodicalIF":5.6000,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of The Energy Institute","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1743967124003350","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
For the purpose of achieving global CO2 reduction, decarbonization at the source of fuels is a practical approach. The transition phase of blending fossil fuels with carbon-free fuels for combustion is a hot topic in the current carbon emission reduction process. In order to achieve efficient and low-pollution combustion of NH3/CH4, the combustion and emission characteristics of NH3/CH4 under single-stage and air-staged combustion methods were numerically investigated in this work. The emissions were compared for different equivalence ratios and different ammonia content conditions. Rate of production (ROP) and sensitivity analysis were performed for NOx, and the reaction path of NH3/CH4 was analyzed. The results indicate that the C-N interaction of the NH3/CH4 mixed combustion process is not significant and turns weaker in the lean flames. HNO intermediate is an important specie for NO generation, and HCN together with HCO intermediate, are essential species for CO generation. NH2 and NH almost dominate the promotion and inhibition of NO generation. Given the contrasting NOx and CO emission behavior of NH3/CH4 in rich and lean flames, the single-stage combustion approach is not suitable. Air-staged combustion achieves both, ensuring the complete burning of NH3 and CH4 while reducing NOx and CO emissions. Moreover, the results suggest that Φpri = 1.2/Φtotal = 0.6 is the optimal NH3/CH4 combustion staging method for controlling NOx emissions.
期刊介绍:
The Journal of the Energy Institute provides peer reviewed coverage of original high quality research on energy, engineering and technology.The coverage is broad and the main areas of interest include:
Combustion engineering and associated technologies; process heating; power generation; engines and propulsion; emissions and environmental pollution control; clean coal technologies; carbon abatement technologies
Emissions and environmental pollution control; safety and hazards;
Clean coal technologies; carbon abatement technologies, including carbon capture and storage, CCS;
Petroleum engineering and fuel quality, including storage and transport
Alternative energy sources; biomass utilisation and biomass conversion technologies; energy from waste, incineration and recycling
Energy conversion, energy recovery and energy efficiency; space heating, fuel cells, heat pumps and cooling systems
Energy storage
The journal''s coverage reflects changes in energy technology that result from the transition to more efficient energy production and end use together with reduced carbon emission.