Study On Pollutant Emissions And Emission Inventory From Open Burning Of Biomass Straw

In China,agricultural crop residue is abundant.Energy structure of rural areas is changing over time,and agricultural crop residue is becoming useless in the traditional agricultural raw materials and cooking in recent years.And the phenomenon of open burning of crop straw is is increasingly serious.The large-scale open burning of straw is not only a waste of resources,but also can cause fire.The smoke and dust generated on the one hand affect the highway and civil aviation,more importantly,the environment could be seriously contaminated,thus having a terribly bad effect on the human health and climate.Therefore,a open burning experiment platform was designed to measure particulate matter（PM）and gas emission factors of three types of crop straws,widely distributed in China:rice,wheat,and corn straw,in flaming and smoldering combustion states with different water contents.First of all,we studied the particle emission characteristics of three kinds of straw.Emission factors of TSP were 11.36～18.00、28.68～48.05、10.46～17.14g/kg from open burning of wheat straws in flaming,smoldering,and vertical combustion state,and were 9.20～13.76、34.85～46.32、8.56～13.12g/kg of rice straws,8.94～15.19、36.44～51.38、8.40～14.65g/kg of corn straw,respectively.It was demonstrated that fine PM dominated the total PM from straw open burning,especially the PM_2.5,and the proportion of PM_2.5 to TSP ranged from 58.72%to 83.07%.PM_2.5 emission factors in smoldering were much higher than that in flaming,about 2.8～5.2 times.Water content were found to be positively correlated with PM emission factors.Besides,PM emission factors in vertical combustion state were slightly higher than that in horizontal combustion state.Then,we studied the gases emission characteristics of three kinds of straw.Emission factors of CO were 43.55～61.57、50.36～79.24、58.51～70.05g/kg in flaming of wheat,rice,and corn straws,and were 80.72～114.92、86.86～108.79、79.73～98.20g/kg in smoldering,40.65～47.25、48.64～57.52、56.34～62.35g/kg in vertical combustion state,respectively.CO emission factors in smoldering were much higher than that in flaming,about 1.2～1.9 times.Water content were found to be positively correlated with CO emission factors.Besides,CO emission factors in horizontal combustion state were slightly higher than that in vertical.The emission factors of NO_x,SO_x and CH₄ were not changing much with the water and combustion state,and the emission factors were 1.67～3.68,0.19～0.43,3.26～7.04g/kg,respectively.Finally,we got the inventory of emissions from crop residue open burning in 2014.In 2014,the total output of three kinds of crop straw in China was 5.8 tons,with an open burning capacity of about 100 million tons.The average proportion crop straw opening burning was about 22%.The province with the highest crop straw opening burning was Henan,followed by Anhui,Hunan,Shandong,Jiangsu,Heilongjiang province.The total emissions of PM₁,PM_2.5,PM₁0 and TSP from crop straw open burning in China in the year 2014 were 194,90×10⁴,353.56×10⁴,400.47×10⁴,448.47×10⁴ t;and the total emissions of CO₂,CO,NO_x,SO_x,CH₄ were 13824.71×10⁴,1092.12×10⁴,31.06×10⁴ 53.91×10⁴,65.06×10⁴ t.The province with the highest crop straw opening burning was Henan,followed by Anhui,Shandong,Heilongjiang,Hunan,Jiangsu province.