Entrained-Phase Adsorption of PCDD/F from Incinerator Flue Gases

Abstract

The emission abatement of polychlorinated dioxins and furans (PCDD/F) issued from municipal solid waste incineration (MSWI) is growing in importance because of more stringent emission standards and general health concern. These substances cannot be separated by conventional gas cleanup processes. They are successfully removed through adsorption onto carbonaceous materials, and the entrained-phase injection of pulverized adsorbents in the flue gas, followed by high-efficiency separation, is widely applied. Operating conditions and results obtained in Flemish MSWIs are given. The results illustrate the excellent overall removal efficiency: the regulation limit of 0.1 ng TEO/Nm3 dry gas at 11% O2 can be achieved. Furans are adsorbed to a slightly higher extent than the dioxins. The PCDD/F removal by carbonaceous adsorbents is thereafter modeled from first principles for the contribution of both entrained-phase (eta1) and cake filtration (eta2) to the overall efficiency (etaT), with dominant parameters being the operating temperature, the dosage and activity of adsorbent, and the fraction of adsorbent in the filter cake. Application of the model equations and comparison of measured and predicted overall efficiencies for the Flemish MSWIs demonstrate the validity of the model, which enables the MSWI operators both to predict the adsorption efficiencies for combinations of major operating parameters and to assess the sensitivity of the process to varying operating conditions. Finally, some practical difficulties encountered with the entrained-phase adsorption are discussed.

A Novel Activated Carbon Injection Method to Enhance PCDD/Fs Removal Efficiency in Flue Gas From a Medical Waste Incinerator in Shanghai, China

“…Tejima et al (1996) reported that the removal efficiency of PCDD/Fs could reach over 99% with activated carbon dosage of 50-100 mg/m 3 . Similar results were reported by Abad et al (2003) and Everaert et al (2003). Gunes et al (2015) reported that the optimum ACI rate for PCDD/Fs was 66 mg/m 3 with removal efficiency was 97% and no significant difference in efficiency was observed at ACI rate of 197 mg/m 3 .…”

Characteristics of PCDD/Fs in a Particles Filtration Device with Activated Carbon Injection

“…Experimental results indicate that I-TEQ decreased markedly when PAC was injected of 17 kg/h. Everaert et al (2003) and Li et al (2008) indicate that increasing the quantity of activated carbon has a limited effect on the overall PCDD/F removal efficiency.…”

Minimum feeding rate of activated carbon to control dioxin emissions from a large-scale municipal solid waste incinerator

“…For examples, Abad et al [4] point out that dioxin removal efficiencies were 92-96% for the AC feeding rate about 100 mg/Nm 3 . Everaert et al [30] indicated that the removal efficiency in MSWI can be achieved 93.3-99.4% in a lower range of AC dosage (50-100 mg/Nm 3 ), but the small effect of increasing the AC dosage over 200 mg/Nm 3 . Kim et al [15] indicated that the removal efficiency of dioxin in MWSI flue gas can be over 98% by dosing AC about 50 mg/Nm 3 for a dual bag filter (DBF) system, but about 200 mg/Nm 3 of AC feeding rate was suggested for a general single bag filter system in MSWI.…”