Mechanisms and characteristics of ash layer formation on bed particles during circulating fluidized bed combustion of Zhundong lignite

Effect of steel slag bed material on ash deposition and Na migration in circulating fluidised bed during Zhundong lignite combustion

“…This is because SS bed material was resistant to Na, leading to the release of more Na species into flue gas. 36 This might bring in severe ash deposition on heat transfer surfaces, as the literature reports. 6,7 in size (Figure 3c).…”

“…Its reaction ability with Na was confirmed low, presenting a Na-resistant property in nature. 34,36 A typical oil shale semi-coke (SC) from an industrial oil shale retort factory with same size with ZD has high contents of SiO 2 and Al 2 O 3 (Table 1) and was used to co-fire with ZD, which is expected to mitigate ash deposition.…”

“…As an extension of our previous work, 36 this paper therefore presents an experimental investigation into the effect of alternative bed material on the characteristics of ash deposition and Na migration in CFB during Zhundong lignite combustion. The mineralogy, morphology and chemistry of the obtained fly ash and deposits on heat transfer surfaces were analysed in detail.…”

“…Given its high melting points (higher than 1500 C) and inert chemical reactivity, 34 SS has been confirmed as a potential bed material for Zhundong lignite combustion to mitigate bed particle agglomeration. 36 However, it may contribute to the enrichment of Na in fly ash and aggravate ash deposition on heat transfer surfaces due to the balance of the total Na amount. The effect of steel slag as bed material on ash deposition and Na migration during Zhundong lignite combustion in CFB has not been examined.…”

“…An annual SS production of 440 Mt by China's steel production industry is reported, 35 with a considerable proportion in the Xinjiang region but is merely regarded as a waste discarded in landfills or stockpiled. Given its high melting points (higher than 1500°C) and inert chemical reactivity, 34 SS has been confirmed as a potential bed material for Zhundong lignite combustion to mitigate bed particle agglomeration 36 . However, it may contribute to the enrichment of Na in fly ash and aggravate ash deposition on heat transfer surfaces due to the balance of the total Na amount.…”