Coke oven gas(COG)and natural gas(NG),both high-calorific by-products derived from the steel industry,have gained prominence as alternative fuels in the sintering process,thereby supporting dual objectives of emission...Coke oven gas(COG)and natural gas(NG),both high-calorific by-products derived from the steel industry,have gained prominence as alternative fuels in the sintering process,thereby supporting dual objectives of emission reduction and carbon neutrality.While existing research on hydrogen-rich gas injection has predominantly concentrated on conventional thin-bed sintering,investigations into its application within thick-bed sintering remain comparatively scarce.Thick-bed sintering,recognized for enhancing energy efficiency and increasing sinter output,encounters challenges such as uneven heat distribution and diminished permeability,which can negatively impact process efficiency and product quality.To address these issues,sinter pot experiments were conducted to assess the effects of NG and COG injection on thick-bed sintering performance.Findings reveal that NG injection in thick beds mirrors the behavior observed in conventional thin-bed sintering,effectively optimizing the process and achieving a carbon reduction potential exceeding 10%.In contrast,COG injection in thick-bed conditions demonstrates notable differences,substantially lowering the solid fuel consumption rate but detrimentally affecting sinter strength and overall production.However,by optimizing the timing of COG injection,it is feasible to improve sinter yield while concurrently reducing solid fuel usage.These outcomes provide valuable insights for the advancement of gas injection technologies in thick-bed sintering,thereby contributing to energy conservation and emission mitigation efforts within the sintering industry.展开更多
A new calcite flux can be directly used for iron ore sintering via the full substitution for burnt lime and limestone.Compared with limestone,calcite flux possesses higher CaO content,lower cost and less impurity elem...A new calcite flux can be directly used for iron ore sintering via the full substitution for burnt lime and limestone.Compared with limestone,calcite flux possesses higher CaO content,lower cost and less impurity elements.After calcination,the activity of calcite flux is improved with the reduction in its particle size,which is consistently better than that of burnt lime and calcined limestone.With the utilization of calcite flux,the formation of liquid phase is promoted,and liquid phase fluidity is improved.In sinter pot tests,the permeability of sinter layer is not deteriorated when calcite flux is added.In addition,the heat and mass transfer conditions are significantly improved with the full substitution of calcite flux for burnt lime and limestone.The positive effect is enhanced with the reduction in calcite flux particle size.After calcite flux particle size is optimized,sinter consolidation characteristics are greatly improved.A denser pilotaxitic sinter microstructure is formed with much higher amount of sillico-ferrite of calcium and aluminum and lower porosity.When the contents of 1–2 and 0–1 mm particles in calcite flux are kept at 70 and 30 wt.%,respectively,sintering indices are overall better.Compared with the base case,the tumble index,productivity and yield are increased by 17.0%,7.4%and 2.9%,respectively,while solid fuel rate is reduced by 9.6%,and carbon emissions in iron ore sintering are greatly reduced.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52474347)Postdoctoral Science Foundation of China(Grant No.2024T171095)the Fundamental Research Funds for the Central Universities(Grant No.2024CDJXY003).
文摘Coke oven gas(COG)and natural gas(NG),both high-calorific by-products derived from the steel industry,have gained prominence as alternative fuels in the sintering process,thereby supporting dual objectives of emission reduction and carbon neutrality.While existing research on hydrogen-rich gas injection has predominantly concentrated on conventional thin-bed sintering,investigations into its application within thick-bed sintering remain comparatively scarce.Thick-bed sintering,recognized for enhancing energy efficiency and increasing sinter output,encounters challenges such as uneven heat distribution and diminished permeability,which can negatively impact process efficiency and product quality.To address these issues,sinter pot experiments were conducted to assess the effects of NG and COG injection on thick-bed sintering performance.Findings reveal that NG injection in thick beds mirrors the behavior observed in conventional thin-bed sintering,effectively optimizing the process and achieving a carbon reduction potential exceeding 10%.In contrast,COG injection in thick-bed conditions demonstrates notable differences,substantially lowering the solid fuel consumption rate but detrimentally affecting sinter strength and overall production.However,by optimizing the timing of COG injection,it is feasible to improve sinter yield while concurrently reducing solid fuel usage.These outcomes provide valuable insights for the advancement of gas injection technologies in thick-bed sintering,thereby contributing to energy conservation and emission mitigation efforts within the sintering industry.
基金Financial supports from National Natural Science Foundation of China(No.52474347)Postdoctoral Science Foundation of China(No.2024T171095)Natural Science Foundation of Chongqing(No.CSTB2023NSCQ-BHX0166)are sincerely acknowledged.
文摘A new calcite flux can be directly used for iron ore sintering via the full substitution for burnt lime and limestone.Compared with limestone,calcite flux possesses higher CaO content,lower cost and less impurity elements.After calcination,the activity of calcite flux is improved with the reduction in its particle size,which is consistently better than that of burnt lime and calcined limestone.With the utilization of calcite flux,the formation of liquid phase is promoted,and liquid phase fluidity is improved.In sinter pot tests,the permeability of sinter layer is not deteriorated when calcite flux is added.In addition,the heat and mass transfer conditions are significantly improved with the full substitution of calcite flux for burnt lime and limestone.The positive effect is enhanced with the reduction in calcite flux particle size.After calcite flux particle size is optimized,sinter consolidation characteristics are greatly improved.A denser pilotaxitic sinter microstructure is formed with much higher amount of sillico-ferrite of calcium and aluminum and lower porosity.When the contents of 1–2 and 0–1 mm particles in calcite flux are kept at 70 and 30 wt.%,respectively,sintering indices are overall better.Compared with the base case,the tumble index,productivity and yield are increased by 17.0%,7.4%and 2.9%,respectively,while solid fuel rate is reduced by 9.6%,and carbon emissions in iron ore sintering are greatly reduced.
