Effect of in-situ modification of coal ash on carbon deposition of Ca-based oxygen carrier in chemical looping combustion
The modified CaSO4-Ash composite oxygen carrier was prepared by in-situ modification of Ca-based oxygen carriers using Zhundong coal ash in a fluidized bed.With the help of CO2 ion flow intensity curves in TG-MS experiments,the influence of the loading amount of Zhundong coal ash on the carbon deposition characteristics during the oxygen carrier reduction reaction process was investigated,and a quantitative coupling experiment of solid-solid reaction and gas-solid reaction was proposed to explore the source of carbon deposition.The results showed that the amount of carbon deposition decreased first and then increased with the increase of the proportion of coal ash in the process of in-situ modification.The CaSO4-10Ash composite oxygen carrier prepared by adding 10%of Zhundong coal ash could minimize the problem of carbon deposition and reduce it by 79.5%.In the solid-solid reaction,with the increase of the coal ash loading ratio,the residual amount of coal coke decreased.When the coal ash loading ratio in the gas-solid reaction was greater than 5%,the performance of the composite oxygen carrier began to decline,and the carbon deposition began to increase;when the coal ash loading ratio was greater than 10%,the amount of carbon deposition that increased as the load ratio continued to increase mainly came from carbon deposit generated by CO decomposition.
chemical looping combustionZhundong coalcoal ash modificationCaSO4 oxygen carrier
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