Emission and distribution of PCDD/Fs and CBzs from two co-processing RDF cement plants in China.

An analysis of the emission and distribution characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and chlorobenzenes (CBzs) from two cement kilns (CK1 and CK2) is done. Six measurements in CK1 showed an increase of PCDD/F emission from 76 to 97 pg I-TEQ/Nm(3) after feeding 10 ton/h RDF (refuse derived fuel). For CK2, the effect of increasing the RDF substitution rates from 0 to 21 t/h on the emission of PCDD/Fs was investigated. The correlation analysis indicated that replacing parts of the conventional fuel with RDF could not increase the emission of PCDD/Fs. Furthermore, the gas/particle partitions of PCDD/Fs and CBzs in stack gas were investigated, indicating that PCDD/Fs and CBzs were more associated in gas phase, especially for the lower chlorinated ones. Moreover, the bag filter fly ash was characterized by its particle distribution, XRD- and EDS-analysis. Additionally, the level of PCDD/Fs in outflowing fly ash escalates for smaller particle size. In order to evaluate the environmental effect on inhabitants, the levels of PCDD/Fs were also determined in samples of ambient air collected in the vicinity of CK2 (~200 m).