Analysis on physicochemical characteristics of fly ash along the heating surfaces of typical MSW grate incineration boiler

Analysis on physicochemical characteristics of fly ash along the heating surfaces of typical MSW grate incineration boiler

Ma Yunfeng¹, Bai Li², Li Xiaodong¹, Lin Xiaoqing¹, Yan Jianhua¹

^{(1.State key laboratory of clean energy utilization, state engineering laboratory of waste incineration technology and equipment, institute of thermal power engineering, zhejiang university, Hangzhou, Zhejiang 310027; 2. Shanghai SUS Environment Co. Ltd., Shanghai 201703)}

Abstract:

The physicochemical characteristics such as elemental composition, ash melting point, crystal structure and morphology characteristics of fly ash along the heating surfaces of typical MSW grate incineation boiler were systematically studied. Under the influences of components, temperature and metal boiling point, the physicochemical characteristics of fly ash changed obviously, especially in the region of 350 ^oC(near the low-temperature secondary superheater). It was found that the element contents and the change of phase structure of Na, K and Ca were the main factors that affected the melting characteristics temperature changes of fly ash, the phase of fly ash were mainly CaSO4, Ca2Al2SiO7, CaAl2Si2O8, K2SO4 and NaKSO4 gradually appeared. Besides, the surface morphologies of fly ash on different heating surfaces occurred spherical, columnar and fibrous characteristics changes, the agglomeration of fly ash showed obvious differences. The increase or enhanced intensity of phase structure of Ca (CaSO4, Ca2Al2SiO7 and CaAl2Si2O8) could promote the agglomeration of fly ash particle, increase the flow temperature (FT) of flying ash, while the increase or enhanced intensity of phase structure of Na and K (K2SO4, Na2SO4 and NaKSO4) could seriously weak the agglomeration of fly ash, reduce the flow temperature of fly ash, consequently affect the melting characteristics of fly ash.

Key words: MSW incineration; grate furnace; waste heat boiler; fly ash; physicochemical characteristics.

Source from Outstanding paper of Environmental Sanitation Engineering in 2020