Online predicting PCDD/F emission by formation pathway identification clustering and Box-Cox Transformation.

The composition of the fuel and operational conditions change dramatically under the long-term operation of municipal solid waste incineration (MSWI). Therefore, it is difficult to provide effective rapid feedback to control PCDD/F emissions, presenting as International Toxic Equivalent Quantity (I-TEQ). To address this problem, a PCDD/F emission prediction method is developed, based on formation pathway identification clustering (FPIC) and Box-Cox transformation (BCT). Meanwhile, 1,2,4-trichlorobenzene is measured by the thermal desorption gas chromatography coupled to tunable-laser ionization time-of-flight mass spectrometry (TD-GC-TLI-TOFMS). In the method, FPIC includes de novo synthesis, chlorobenzene(CBz)-route synthesis, chlorophenol (CP)-route synthesis, and the chlorination of dibenzofuran (DD) or dibenzodioxin (DF). The PCDD/F emission data was divided into Cluster 1 (I-TEQ>0.1 ng/Nm) and Cluster 2 (I-TEQ<0.1 ng/Nm) by FPIC due to PCDD/F in Cluster 1 main from CP-route and PCDD/F in Cluster 2 main from de novo synthesis and CBz-route synthesis. Also, the BCT was used to transform the I-TEQ and 1,2,4-trichlorobenzene data and to construct effective models. The accurate and precise PCDD/F emissions are predicted with the vast majority of error percentage within [ -40%, 40% ], and errors within [ -0.126, 0.016 ] I-TEQ (ng/Nm). The absolute value of the relative difference between predicted I-TEQ and measured I-TEQ (|RD|) of the linear model constructed by the method has a significant reduction to 20.28%. FPIC and BCT can be used as an effective method to online predict PCDD/F emission in long-term operation thereby allowing the rapid operational feedback to control PCDD/F emission from the incinerator.