The high temperature air combustion(HiTAC) process in gas suspension calcinations(GSC) was studied by using a CFD software FLUENT that can simulate the three-dimensional physical model of GSC with the k-epsilon turbul...The high temperature air combustion(HiTAC) process in gas suspension calcinations(GSC) was studied by using a CFD software FLUENT that can simulate the three-dimensional physical model of GSC with the k-epsilon turbulent viscous model, PDF non-premixed combustion species model, P1 radiation model, thermal and prompt NO pollution model. The simulation vividly describes the distributions of the temperature, velocity and consistency fields. Finally, the optimal operation conditions and igniter configuration of particular fuel combustion are obtained by analyzing and comparing the simulation results. And the emission quantity of NOx, CO and CO2 deduced from computation can play a role as reference. These optimal and estimated values are beneficial to practical operation.展开更多
In this paper,the effect of high temperature calcination on the structure and properties of bauxite-based homogeneous clinkers calcined at different temperatures for different durations was studied.The results show th...In this paper,the effect of high temperature calcination on the structure and properties of bauxite-based homogeneous clinkers calcined at different temperatures for different durations was studied.The results show that with the rising of calcination temperature and the prolonging of holding time,the volume density of bauxite-based homogeneous clinkers increases and the apparent porosity decreases.After high temperature calcination,the linear expansion of bauxitebased homogeneous clinker is smaller than that of the non-calcined ones.Whether calcined at high temperatures or not,the thermal shock resistance of bauxite-based homogeneous clinkers is good.The crystalline phases of bauxite-based homogeneous clinkers are mainly mullite and corundum.There is more glass phase in the bauxite-based homogeneous clinkers without calcination.After calcination at high temperatures the glass phase content decreases significantly,and the mullite crystals develop better forming the cross-network structure.展开更多
The effect of calcium oxide additive in iron oxide sorbent for hot gas desulfurization was investigated by XRD and TPR techniques.XRD characterization showed that CaO was highly dispersed after the calcination of sorb...The effect of calcium oxide additive in iron oxide sorbent for hot gas desulfurization was investigated by XRD and TPR techniques.XRD characterization showed that CaO was highly dispersed after the calcination of sorbents.Calcium sulfate formed in the desulfurization was decomposed and regenerated to CaO by reacting with CO before the next sulfidation process.Calcium participated in every sulfidation/regeneration cycle and contributed to the enhancement of sulfur capacity.The TPR results showed that the reduction temperature of the sorbent increased with the increase of the content of calcium.Calcium played a role of retarding reduction.Therefore,the addition of calcium oxide additive will benefit the utilization of iron oxide sorbent in strongly reducing atmospheres.展开更多
Zn-Mn-Cu/SC（U） sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke（SC）as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitra...Zn-Mn-Cu/SC（U） sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke（SC）as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC（U） sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC（U） sorbents.展开更多
基金Project (60634020) supported by the National Natural Science Foundation of China
文摘The high temperature air combustion(HiTAC) process in gas suspension calcinations(GSC) was studied by using a CFD software FLUENT that can simulate the three-dimensional physical model of GSC with the k-epsilon turbulent viscous model, PDF non-premixed combustion species model, P1 radiation model, thermal and prompt NO pollution model. The simulation vividly describes the distributions of the temperature, velocity and consistency fields. Finally, the optimal operation conditions and igniter configuration of particular fuel combustion are obtained by analyzing and comparing the simulation results. And the emission quantity of NOx, CO and CO2 deduced from computation can play a role as reference. These optimal and estimated values are beneficial to practical operation.
文摘In this paper,the effect of high temperature calcination on the structure and properties of bauxite-based homogeneous clinkers calcined at different temperatures for different durations was studied.The results show that with the rising of calcination temperature and the prolonging of holding time,the volume density of bauxite-based homogeneous clinkers increases and the apparent porosity decreases.After high temperature calcination,the linear expansion of bauxitebased homogeneous clinker is smaller than that of the non-calcined ones.Whether calcined at high temperatures or not,the thermal shock resistance of bauxite-based homogeneous clinkers is good.The crystalline phases of bauxite-based homogeneous clinkers are mainly mullite and corundum.There is more glass phase in the bauxite-based homogeneous clinkers without calcination.After calcination at high temperatures the glass phase content decreases significantly,and the mullite crystals develop better forming the cross-network structure.
基金the National Key Fundamental Research Project of the Ministry of Science and Technology(973 2005CB221203)
文摘The effect of calcium oxide additive in iron oxide sorbent for hot gas desulfurization was investigated by XRD and TPR techniques.XRD characterization showed that CaO was highly dispersed after the calcination of sorbents.Calcium sulfate formed in the desulfurization was decomposed and regenerated to CaO by reacting with CO before the next sulfidation process.Calcium participated in every sulfidation/regeneration cycle and contributed to the enhancement of sulfur capacity.The TPR results showed that the reduction temperature of the sorbent increased with the increase of the content of calcium.Calcium played a role of retarding reduction.Therefore,the addition of calcium oxide additive will benefit the utilization of iron oxide sorbent in strongly reducing atmospheres.
基金supported by the National Basic Research Program of China(2012CB723105)the National Natural Science Foundation of China(20976117)the Technological Innovation Programs of Higher Education Institutions in Shanxi(2013JYT113)
文摘Zn-Mn-Cu/SC（U） sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke（SC）as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC（U） sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC（U） sorbents.
文摘采用共沉淀-高温固相法在氧气气氛下合成球形Li Ni0.8Co0.15Al0.05O2正极材料。通过XRD、SEM、恒电流充放电测试和交流阻抗测试等手段分析了氧化铝、氢氧化铝和异丙醇铝三种铝源对合成材料的结构、形貌以及电化学性能的影响。结果表明,以三种不同铝源所合成的正极材料均具有良好的层状结构。用异丙醇铝合成的正极材料具有最小的一次颗粒,球型度较好,具有优异的电化学性能,在0.2 C下首次放电比容量为189.22 m Ah/g,50次循环后容量保持率为84.2%。然后,通过EIS测试分析了不同铝源对合成材料性能影响的原因。
