Study on the emission characteristics and source profiles of volatile organic compounds for typical cement plants in China

Accurate depiction of volatile organic compounds (VOCs) emission characteristics and source profiles is essential for formulation of VOCs control strategies of cement plants. Four representative cement kilns, including one shaft kiln and three new suspension preheater (NSP) kilns with different cement clinker capacity, were chosen to survey the source profile, chemical reactivity and emission characteristics of VOCs during cement clinker production. The total mass concentrations of analyzed 98 VOC species was 118181.9 ug/m³ in shaft kiln, about 30 times higher than the concentration in NSP kilns. And each concentration of 98 species of VOCs in flue gas of shaft kiln was higher than those in flue gas of NSP kilns except for Chloromethane, Chloroethane and Bromomethane. The group of alkanes and alkenes contributed 86.6% to the total mass concentrations of shaft kilns, while sum of alkenes, aldehydes and halogenated hydrocarbons contributed 59.9%-68.3% in three NSP kilns. Most abundant compounds generated in shaft kiln were Ethane, Ethylene and Propane, while in NSP kilns they were Acetaldehyde, Ethylene and Acetylene. Ozone formation potentials (OFP) of each VOC species was calculated, and VOC species with highest OFP contributions in the four tested kilns were similar. The overall emission factor (g/ (t of cement clinker)) of 98 VOCs for the shaft kiln was determined to be about 320.7 g/t, whereas it fell within the range of 5.1-14.3 g/t for NSP kilns, which far less than that of shaft kiln, suggesting the better combustion performance of NSP kilns. Furthermore, emission factors of speciated VOCs were also provided and discussed. Results of overall and speciated VOCs emission characteristics released from cement kilns can be used to formulate targeted reduction measures of VOCs, improve and update VOCs emission inventory for cement industries, thereby making source appointment analysis and atmospheric model simulation more accurate.

*Corresponding author: hztian@bnu.edu.cn (Prof. / Dr. H.Z., Tian); Tel & Fax: 86-10-58800176

Acknowledgment: This work is funded by NSFC of China (21777008 and 21377012), MOST of China (2018YFC0213202, 2016YFC0201501) and MEE of China (DQGG0209).