石油焦中钒和镍对高铁煤灰渣黏-温特性的影响

高硫石油焦与煤气流床共气化是其高效洁净利用的可行途径，气化灰渣的黏-温特性决定着气化炉的稳定运行，石油焦灰富含的V和Ni可引起共气化灰渣的黏-温特性变化，然而石油焦中的V和Ni对高铁煤灰黏-温特性的影响尚不清楚。选择一种高铁的气化煤灰，通过添加V₂O₅和NiO研究了V和Ni对高铁煤灰渣黏-温特性的影响规律。结果表明：随着V₂O₅和NiO添加量的增加，全液相的灰渣黏度呈降低趋势，降温过程中V与Al、Fe形成了尖晶石，导致灰渣黏度急剧增加，使灰渣黏-温特征曲线逐渐趋向结晶渣，导致气化炉可操作温度范围变窄；灰渣中Fe更易与V形成尖晶石(FeV₂O₄)晶体析出，Fe可促进灰渣中Ni还原为金属Ni，Ni与Fe团聚形成合金小球析出，并起到非均相晶核作用，促进尖晶石在其表面析出；V和Ni均可导致FeO以固相析出，进而使降温过程中液相渣的黏度增加，这也使含V和Ni的高铁煤灰渣黏度随着温度降低时的增加速率比高钙灰渣更快。

Effect of Vanadium and Nickel in Petroleum Coke on the Viscosity-Temperature Characteristics of High-Fe Coal Ash and Slag

The entrained-flow co-gasification of high-sulfur petroleum coke with coal is deemed as a feasible way to achieve its efficient and clean utilization. The stable operation of gasifier is determined by the viscosity-temperature characteristics of gasified ash and slag. Although the V and Ni, which are rich in petroleum coke, can cause the change in the viscosity-temperature characteristics of co-gasified ash and slag, their effect on the viscosity-temperature characteristics of high-Fe coal ash and slag is still unclear. The high-Fe gasified coal ash and slag were selected to study the influence law of V and Ni on the viscosity-temperature characteristics of high-Fe coal ash and slag by adding V₂O₅ and NiO. The results show that the viscosity of the full-liquid phase ash and slag decreases with the increase of V₂O₅ and NiO addition, and V reacts with Al and Fe to form spinel (FeV₂O₄) in the cooling process, which causes a sharp increase in the viscosity of ash and slag and then makes the viscosity-temperature characteristic curve of ash and slag gradually tend to be the same as that of crystalline slag, thus narrowing the range of temperatures over which the gasifier operates. Fe in the ash and slag was easier to react with V and form spinel crystal (FeV₂O₄) precipitate, and can promote the reduction of Ni in the ash and slag to metallic Ni, which agglomerates with metallic Fe to form alloy grains and then is precipitated, playing the role of heterogeneous crystal nucleus, and finally promotes the precipitation of spinel on its surface. To sum up, both V and Ni can cause the precipitation of FeO in the form of solid phase, thus increasing the viscosity of the liquid-phase slag in the cooling process, which is also the reason why the viscosity of high-Fe coal ash and slag containing V and Ni increases faster than that of high-calcium ash and slag as the temperature decreases.