Effect of the Coal Fly Ash Blending Ratio on Biomass Slagging Structure Modification and Alkali Metal Migration.
Shuo YangShaohui WangYudong FuJie CuiYupeng ZhangYumeng WangYuhang WangXi WangPublished in: Energy & fuels : an American Chemical Society journal (2023)
The analysis of ash deposition samples by electron microscopy (EM), scanning electron microscopy (SEM)/energy dispersive scanning (EDS), and X-ray diffraction (XRD) was carried out at three sampling points of a one-dimensional furnace (sampling temperatures were T L5 = 960 °C, T L6 = 855 °C, and T L7 = 820 °C, respectively). The improvement of ash deposition characteristics of biomass combustion with the different addition ratios of coal fly ash (CFA) ( M r = 1:1, 1.5:1 or 2:1) and the heterogeneous removal of gas phase alkali metal heterogeneous were studied. The results showed that under the condition of M r = 1:1, the ash sample presented a three-dimensional porous loose structure like "coral reef" with the rice husk ash as the skeleton and the combustion products of CFA as the bonding point. The spherical and filamentous crystals mainly composed of SiO 2 , Al 2 O 3 , and silicates were distributed in the slag, and the surfaces of these crystals were accompanied by the eutectic composite salt of K-Al-Si with a high melting point, reflecting the heterogeneous curing effect of CFA on the gas phase migration of the alkali metal (K). With the decreasing addition ratio of CFA ( M r = 1.5:1 or 2:1), the spherical and filamentous crystals were increased in the slag. MgO, Fe 2 O 3 , and Al 2 O 3 may be involved in the formation of high-temperature refractory Mg-Fe-aluminate, Ca- and Mg-silicate, which were the precursors of the rigid slag. The alkali metals mostly presented in the form of K 2 O and KCl in the gas-solid conversion under the temperature effect, serving as binders for bridging, agglomeration, and slagging of the above precursors. In addition, the kalium enrichment was accompanied by Al and S in the CFA, indicating that the Al- and S-active sites have obvious adsorption to kalium.
Keyphrases
- electron microscopy
- municipal solid waste
- sewage sludge
- anaerobic digestion
- heavy metals
- room temperature
- particulate matter
- high resolution
- high temperature
- ionic liquid
- wastewater treatment
- risk assessment
- magnetic resonance
- health risk
- staphylococcus aureus
- escherichia coli
- biofilm formation
- solid phase extraction
- metal organic framework
- highly efficient
- solid state
- contrast enhanced
- candida albicans
- simultaneous determination