燃油锅炉燃烧过程SO_2的生成与排放特征

Generation and emission characteristics of SO_2 from fuel oil combustion in boilers

燃料燃烧过程是大气污染物的重要来源之一,对人体健康、空气质量和气候变化产生非常重要的影响。以62台燃油锅炉(≤10.5 MW)的燃料特性分析数据和SO2排放实测数据为基础,通过统计分析方法,研究了燃油燃烧过程中燃油硫含量S和过量空气系数α对硫的转化率、SO2排放因子和排放浓度的影响,获得了基于燃料消耗量、燃料发热量的SO2排放因子EFC、EFH以及SO2标态折算浓度CS′O2与硫含量S间的关联式。结果表明,在过量空气系数α>1的燃油燃烧过程中,EFC、EFH、CS′O2与燃油硫含量S呈现出显著的线性正相关性,而与过量空气系数α无关,其关系式分别为:EFC=18.86602×S,EFH=443.78751×S,CS′O2=1 509.28337×S;硫转化率η和基于燃料硫含量的SO2排放因子EFS则与燃油硫含量S和过量空气系数α无关,其平均值分别为96.3%和1.93 kg/kg。

The combustion of fuels in boilers is one of important sources of air pollutants.It has very important impacts on human health,air quality and climate changes.The impacts of sulphur contents of fuel oil and excess air coefficients on sulphur conversion rates,emission factors and emission concentrations of SO2 were studied by means of statistical analysis method and based on the fuel oil analysis data and the actual test data of SO2 emissions from 62 oil-fired boilers in China,actual capacity of boilers≤10.5 MW.Furthermore,the mathematical relationships of SO2 emission factors based on fuel consumption（EFC）and fuel heating value（EFH）,and emission concentrations of SO2（C′SO2） converted into standard state and excess air coefficient is 1.2,with sulphur contents were obtained.The results indicate that in fuel oil combustion,excess air coefficients〉1,EFC,EFH,and C′SO2 present a highly significant positive linear correlation with sulphur contents,and are independent of excess air coefficients.These correlations are EFC=18.86602×S,EFH=443.78751×S,and C′SO2=1 509.28337×S,respectively.Sulphur conversion rates and emission factors based on sulphur content of fuel oil are independent of sulphur contents and excess air coefficients,and their average values are 96.3% and 1.93kg/kg,respectively.