Characteristics of VOCs source composition profiles in industrial kilns with different fuel types in Guangxi's ceramic industry

To advance the management of emissions of volatile organic carbons (VOCs) from kilns with different fuel types used in the ceramic industry, this study investigated eight natural gas and coal-fired kilns in Guangxi. Samples were collected in Summa canisters under negative pressure, followed by analysis by gas chromatography mass spectrometry with flame ionization detection (GC-MS/FID). The ozone formation potential (OFP) and factors associated with the VOCs emissions were determined in order to establish emission profiles for industrial furnaces and kilns of different fuel types. With natural gas and coal-fired furnaces, there was a high degree of similarity in the components of the VOCs for the different fuel types, and OVOCs accounted for 78.84% and 71.82% of the VOCs, respectively; these were followed by alkanes (8.97% and 16.48%) and alkenes (6.24% and 5.36%), respectively. However, there were some distinct differences in the ratios of individual components. For example, VOCs species emitted from natural gas furnaces were mainly acrolein (28.14%), propanal (23.17%), acetone (11.79%), and acetaldehyde (5.42%), whereas those from coal-fired furnaces were mainly propanal (44.70%), acrolein (8.65%), isobutane (6.63%), and acetaldehyde (6.11%). The gas- and coal-fired kilns were similar in their OFPs, and in both the VOCs emissions were dominated by OVOCs, which accounted for 84.36% and 83.62% respectively; these were followed by olefins (11.27% and 10.07%, respectively). Acrolein (38.38%), propionaldehyde (30.03%), and acetaldehyde (6.48%) were the dominant species contributing to the OFP of VOCs emissions in natural gas kilns, whereas propionaldehyde (58.96%), acrolein (12.01%), and acetaldehyde (7.44%) were the dominant species with coal-fired kilns, Overall, this study derived localized VOCs emission factors for natural gas and coal-fired kilns of 0.08 g·m−3 and 10.73 g·t−3, respectively, and it is evident that the management of VOCs emissions represents an environmental problem that should not be ignored. Also, the VOCs emission factor of natural gas kilns is significantly lower than that of coal-fired kilns, indicating that converting coal-fired kilns to natural gas is conducive to reducing VOCs emissions.