Emission characteristic and environmental impact of process-based VOCs from prebaked anode manufacturing industry in Zhengzhou, China

Abstract

Process-based samples of VOCs were collected in three prebaked anode manufacturers to analyze the emission characteristics of calcining and baking process. Besides, the ratios of diagnostic VOCs were investigated, and the OH loss rate (LOH), ozone potential formations (OFP) and secondary organic aerosol formations potential (SOAFP) of VOCs were calculated to estimate environmental impact. Results shows that the VOCs concentrations emitted from calcining and baking were in the range of 213.5–1081.8 μg/m3, and 2530.1–26774.8 μg/m3, respectively. Aromatics accounted 51.8% and 68.7% and naphthalene accounted 22.6% and 30.7% for total VOCs in calcining or baking, respectively. VOCs emission factors of prebaked anode manufacturing industry were averaged 0.198 ± 0.153 kg/t, and at least 3.2 ± 2.5 kt and 5.6 ± 4.4 kt VOCs were released in China and global, respectively, in 2017. The measured diagnostic ratios of VOCs such as benzene, toluene, xylene, ethylbenzene, naphthalene, styrene, and CS2 were expected to be useful for source identification. VOCs emitted from baking had more adverse impact on environment than calcining, and whether in calcining or baking, aromatics were the largest contributor to LOH, OFP and SOAFP, means that should be controlled primarily.