Removal of Chlorinated Aromatic Organic Compounds from MWI with Catalytic Filtration

Abstract

Adsorption with activated carbon and catalytic oxidation with an appropriate catalyst are two methods for the effective removal of gaseous dioxin-like congeners from flue gases. The removal efficiencies of chlorobenzene/chlorophenol (CBz/CPh) from gas streams achieved by an "activated carbon injection + bag filter" (ACI + BF) system in a municipal waste incinerator (MWI) and catalytic filter (CF) system installed in a pilot-scale module are evaluated in this study via sampling and analysis. Real flue gas obtained prior to activated carbon injection in the dust of an MWI is introduced and fed into a pilot-scale module to evaluate CBz/CPh removal efficiencies. The CBz and CPh removal efficiencies achieved with the catalytic filtration 180°C are 78.3% and 77.4%, respectively, and the efficiencies increase significantly with increasing temperature. Due to the different removal mechanisms of the ACI + BF and CF technologies, increasing removal efficiencies with more Cl-substituted CBz/CPh congeners in flue gas are found with ACI + BF technology as a result of higher boiling points of highly Cl-substituted CBz/CPh congeners. Thanks to the destruction of contaminants by a catalyst, relatively lower CBz/CPh concentrations (158 and 177 ng/g, respectively) were measured in the fly ash of the CF module compared with those in the ACI + BF system (301 and 371 ng/g of CBz and CPh, respectively). Since AC injection is not needed in the CF module, lower CBz/CPh contents and lower discharge of fly ash are observed compared with those seen with the ACI + BF technology. If the ACI + BF technology is replaced by CF technology, the discharge factors of CBz and CPh (including emission and fly ash) will be reduced significantly, from 11.9 and 15.3 mg/ton waste, respectively, to 6.13 and 6.11 mg/ton waste. Moreover, a reduced environmental impact is expected with the application of CF technology due to the lower CBz/CPh concentrations in fly ash compared with those seen with the ACI + BF technology.

Formation, Measurement, and Control of Dioxins from the Incineration of Municipal Solid Wastes: Recent Advances and Perspectives

“…The chloroaromatic it is still the key mechanistic step, in which, some precursors, including CPh, CBz, and PCBs, are formed. Dickson et al 63 added 13 C-PCP to the model fly ash and found that no scrambled PCDD was detected in the de novo process, meaning that the CPh molecule would not react with the carbon matrix to form PCDD. However, Hell et al 73 found that approximately 40% of the total PCDD was formed through condensation of de novo created chlorophenols.…”

“…Before subsequent cleanup processing, 13 C-1,2,3,7,8,9-HxCDD in the alternate recovery stock solution was added for the assessment of purification efficiency. Finally, samples are concentrated and 13 C labeled recovery standard stock solution was added before the analysis by HRGC/HRMS. HRGC/HRMS has been used as the official method for trace analysis of dioxins and can provide accurate measurements for homologues of PCDD/F.…”

Bimodal effect of water on V2O5/TiO2 catalysts with different vanadium species in the simultaneous NO reduction and 1,2-dichlorobenzene oxidation

“…This technology allows to hold and destroy through catalytic oxidation reaction the PCDD/Fs from solid phase (adsorbed in dust) and gas phase. Hung et al [23] compared the chlorobenzenes and chlorophenols removal efficiencies of catalytic filters and the system composed by the injection of active carbon followed by bag filter. The former was more efficient than the latter, especially as the temperature was increased [23].…”

“…Hung et al [23] compared the chlorobenzenes and chlorophenols removal efficiencies of catalytic filters and the system composed by the injection of active carbon followed by bag filter. The former was more efficient than the latter, especially as the temperature was increased [23].…”

Sorption of Volatile Organic Compounds on Organic Substance-Modified Titanate Nanotubes

“…The problem of VOCs has gained widespread attention regarding the air quality in indoor environments (Jia et al, 2008;Parra et al, 2008;Ohura et al, 2009;Pei et al, 2013;Geiss et al, 2014). Several investigators have developed many methods for removing VOCs in the air (Ruddy and Carroll, 1993;Khan and Ghoshal, 2000;Hung et al, 2014). Thermal oxidation has high VOC removal efficiency, but is used only with a high concentration of organic compounds.…”