小型燃油锅炉大气污染物排放特征

燃料燃烧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严重影响. 以85台小型燃油锅炉(≤10.5 MW)的颗粒物(PM),SO₂和NO_x排放实测数据为基础,通过统计分析方法,研究了大气污染物PM,SO₂和NO_x的排放特征及其影响因素,分析了我国小型燃油锅炉PM,SO₂和NO_x的排放现状. 结果表明,在未采取控制措施的条件下,ρ(PM)与燃油灰分〔w(灰分)〕和硫含量〔w(S)〕无关;而在过量空气系数(α)>1时,ρ(SO₂)与燃油w(S)之间呈现显著的正线性相关性;ρ(NO_x)与燃油氮含量〔w(N)〕不具有相关性,而随过量空气系数的增大而增大. 实测得到ρ(PM),ρ(SO₂)和ρ(NO_x)平均值分别为20.0,259.9和318.2 mg/m3;所有测试锅炉的ρ(PM)远远小于《锅炉大气污染物排放标准》(GB13271—2001)所规定的最高允许排放限值,有90%以上的锅炉达到ρ(SO₂)最高允许排放限值,有84%的锅炉达到ρ(NO_x)最高允许排放限值. 

Emission Characteristics of Air Pollutants from Small Oil-fired Boilers

The combustion of fuels in boilers is an important source of air pollution, which seriously affects human health, air quality and climate change. The emission characteristics of particulate matter (PM), SO₂ and NO_x and their influencingfactors were studied by statistical analysis method using field data from 85 small oil-fired boilers (actual capacity of boilers ≤10.5 MW). Additionally, the status of PM, SO₂, and NO_x emissions in China from small oil-fired boilers was discussed. The results indicated that PM emission concentrations were not significantly correlated with the contents of oil ash and sulphur under conditions without control measures. The SO₂ emission concentrations presented a significant correlation with oil sulphur content when the excess air coefficient α was over 1. Moreover the NO_x emission concentration was not significantly correlated with oil nitrogen content, which increased with increasing α. The average emission concentrations of PM, SO₂, and NO_x obtained by actual monitoring were 20.0, 259.9, and 318.2 mg/m3, respectively. PM emission concentrations of all tested boilers were far less than the maximum acceptable emission concentration (MAEC) prescribed in Emission Standard of Air Pollutants for Coal-burning, Oil-burning, Gas-fired Boiler (GB13271-2001). More than 90% of all tested boilers met the MAEC for SO₂, and 84% met the MAEC for NO_x.