MSW pyrolysis volatiles' reforming by incineration fly ash for both pyrolysis products upgrading and fly ash stabilization

Yuzhen Tang; Dezhen Chen; Yuheng Feng; Yuyan Hu; Lijie Yin; Kezhen Qian; Guoan Yuan; Ruina Zhang

doi:10.1016/j.chemosphere.2022.137536

MSW pyrolysis volatiles' reforming by incineration fly ash for both pyrolysis products upgrading and fly ash stabilization

Chemosphere. 2023 Feb:313:137536. doi: 10.1016/j.chemosphere.2022.137536. Epub 2022 Dec 14.

Authors

Yuzhen Tang¹, Dezhen Chen², Yuheng Feng³, Yuyan Hu³, Lijie Yin³, Kezhen Qian³, Guoan Yuan⁴, Ruina Zhang⁵

Affiliations

¹ Thermal and Environmental Engineering Institute, Mechanical Engineering College, Tongji University, Shanghai, 201804, China; Shanghai Engineering Research Center of Multi-source Solid Wastes Co-processing and Energy Utilization, Shanghai, 201804, China. Electronic address: 2030241@tongji.edu.cn.
² Thermal and Environmental Engineering Institute, Mechanical Engineering College, Tongji University, Shanghai, 201804, China; Shanghai Engineering Research Center of Multi-source Solid Wastes Co-processing and Energy Utilization, Shanghai, 201804, China. Electronic address: chendezhen@tongji.edu.cn.
³ Thermal and Environmental Engineering Institute, Mechanical Engineering College, Tongji University, Shanghai, 201804, China; Shanghai Engineering Research Center of Multi-source Solid Wastes Co-processing and Energy Utilization, Shanghai, 201804, China.
⁴ Thermal and Environmental Engineering Institute, Mechanical Engineering College, Tongji University, Shanghai, 201804, China; Shanghai Institute for Design and Research on Environmental Engineering Co. Ltd, Shanghai, 200232, China.
⁵ Shanghai Institute for Design and Research on Environmental Engineering Co. Ltd, Shanghai, 200232, China.

PMID: 36528161
DOI: 10.1016/j.chemosphere.2022.137536

Abstract

The effective disposal of municipal solid wastes (MSW) and its incineration-derived fly ash (IFA), which contains large amounts of heavy metals (HMs) and chlorine (Cl), is an urgent task. In this study, IFA was used to reform MSW pyrolysis volatiles within 500-800 °C. The changes of reformed pyrolysis products, the migration characteristics of HMs and Cl between IFA and pyrolysis products were investigated. The results indicated that the O- and Cl-containing compounds in pyrolysis oil tended to decrease, light hydrocarbons and its calorific value increased accordingly after reforming; more CH₄ and H₂ gases were produced concurrently. The increase in reforming temperature enhanced these trends. The IFA absorbed Cl from volatiles during reforming, which reduced HCl in the gas product. The toxicity equivalent (TEQ) of PCDD/Fs in IFA decreased dramatically from 0.47 μg/kg to 0.0055 μg/kg after reforming at 500 °C, and it decreased with increasing reforming temperature. Some of the HMs' concentrations in the used IFAs increased, but their leaching capacity all decreased significantly at 800 °C except for Cr. The used IFA at 800 °C (IFA-800) corresponded to the lowest HMs leaching concentrations and could meet the landfill requirements; while the used IFA at 500 °C (IFA-500) corresponded to the maximum carbon deposition of 14.63 wt%, providing the energy source for its melting. Therefore 800 °C was recommended for harmless disposal of IFA, and 500 °C was better for a further melting of IFA., The contamination of pyrolysis liquid caused by inorganic Cl-containing compounds at 500 and 800 °C with much lower levels than the original. This study showed the hazardous properties of IFA can be dampened after interacting with MSW pyrolysis volatiles within the tested temperature range, and provided a good chance for the simultaneous disposal of IFA and recovery of high-quality MSW pyrolysis products.

Keywords: Catalytic reforming; Chloride; Heavy metals (HMs); Incineration fly ash (IFA); Municipal solid wastes (MSW); Pyrolysis volatiles.

MeSH terms

Chlorine
Coal Ash
Dibenzofurans
Gases
Incineration
Metals, Heavy* / analysis
Polychlorinated Dibenzodioxins* / analysis
Pyrolysis
Solid Waste

Substances

Coal Ash
Solid Waste
Dibenzofurans
Polychlorinated Dibenzodioxins
Metals, Heavy
Gases
Chlorine