Investigation on the Emission Difference of Air Pollutants from Common Residential Coal Stoves and Suggestions for Emission Reduction

Abstract

To explore the difference in the emission of air pollutants from coal stoves, five new and common residential coal stoves (square briquette, baffled heat exchange, heating and cooking integrated gasification positive burning, and gasification reverse burning stove) were selected. The emission level of major air pollutants was determined using simulated combustion in the laboratory for quantitatively evaluating the environmental effects of different coal stoves. Moreover, the factors and reasons for the differences were identified, and suggestions for the reduction of emission were proposed. The results showed that: ① the emissions of air pollutants from different coal stoves were significantly different; the heating and cooking integrated stove had the largest emission intensity (2.9 kg ·t-1) of air pollutants (SO2, NOx, and TSP), which was 1.6 times of the average value, and the square briquette stove had the lowest emission level, which was 65% of the average value. ② The emissions of gaseous pollutants from the coal stoves in different combustion stages also showed evident differences. In the high-fire stage, the NOx emission concentration of the square briquette stove was 0.49 mg ·m-3, which was 45%-72% lower than that of the other stoves; the SO2 emission concentration of the gasification reverse burning stove was 1.38 mg ·m-3, which was 28% lower than that of the other stoves. ③ The application technology and combustion type were the main factors affecting the emission levels of the coal stoves. The stove with square briquette technology and gasification reverse burning technology could have great environmental benefit. However, the cost of the two stoves was 20 and 18 thousand yuan, respectively, which was clearly higher than that of the other types of stoves. ④ Considering the difference in the emission of air pollutants from the different stoves, it was suggested to adopt differentiated economic policy and strict emission and product standards, promoting the use of energy-saving and environment-friendly coal stoves to reduce the emission of air pollutants from coal-fired stoves.