用顶吹 CO2 - Na OH溶液体系模拟了 RH- KTB顶吹氧溶氧过程。通过对碱液吸收 CO2 反应动力学的研究 ,考察了操作参数对 RH- KTB顶吹氧脱碳过程中溶氧反应的影响。结果表明 :提高气相中氧分压、增加提升氩气流量或采用低枪位喷吹都有利...用顶吹 CO2 - Na OH溶液体系模拟了 RH- KTB顶吹氧溶氧过程。通过对碱液吸收 CO2 反应动力学的研究 ,考察了操作参数对 RH- KTB顶吹氧脱碳过程中溶氧反应的影响。结果表明 :提高气相中氧分压、增加提升氩气流量或采用低枪位喷吹都有利于加速溶氧脱碳。实验中还发现 :顶吹氧气流量对容积传质系数影响很小 。展开更多
The flow and mixing characteristics of molten steel during the vacuum circulation refining, including RH(Ruhrstahl Heraeus) and RH KTB(Ruhrstahl Heraeus Kawasaki top blowing) processes, were investigated on a 1/5 ...The flow and mixing characteristics of molten steel during the vacuum circulation refining, including RH(Ruhrstahl Heraeus) and RH KTB(Ruhrstahl Heraeus Kawasaki top blowing) processes, were investigated on a 1/5 linear scale water model of a 90 t multifunction RH degasser. The circulation rate was directly and more accurately determined, using a new method by which the more reliable results can be obtained. The fluid flow pattern and flow field in the ladle were demonstrated, observed and analyzed. The mixing time of liquid in the ladle was measured using electrical conductivity method. The residence time distribution in the RH model was obtained by tracer response technique. The influence of the main technological and geometric factors, including the gas top blowing (KTB) operation, was examined. The results indicated that the circulation rate of molten steel in the RH degasser can be fairly precisely calculated by the formula: Q lp =0.0333 Q 0.26 g D 0.69 u D 0.80 d(t/min), where Q g-the lifting gas flow rate (NL/min); D u and D d-the inner diameters of the up and down snorkels (cm), respectively. The maximum value of circulation rate of molten steel in the case of the 30 cm diameters either of the up and down snorkels for the RH degasser (the “saturated” rate) is approximately 31 t/min. The corresponding gas flow rate is 900 NL/min. Blowing gas into the vacuum chamber through the top lance like KTB operation does not markedly influence the circulatory flow and mixing characteristics of the RH process under the conditions of the present work. There exist a major loop and a large number of small vortices and eddies in the ladle during the RH refining process. A liquid liquid two phase flow is formed between the descending stream from the down snorkel and the liquid around the stream. All of these flow situation and pattern will strongly influence and determine the mixing and mass transfer in the ladle during the refining. The correlation between the mixing time and the stirring energy density is τ m∝ε -0.50 for the RH degasser. The mixing time rapidly shortens with an increase in the lifting gas flowrate. At a same gas flow rate, the mixing times with the up and down snorkel diameters either of 6 and 7 cm are essentially same. The 30 cm diameters either of the up and down snorkels for the RH degasser would be reasonable. The concentration time curve showed that three circulation cycles are at least needed for complete mixing of the liquid steel in the RH degasser.展开更多
以西昌钢钒200 t RH-KTB真空精炼装置为原型,借助CFD数值模拟的方法,通过分析射流马赫数、射流动压和半射流宽度,研究了常压及真空条件下超音速氧气射流的特性。研究结果表明:射流马赫数随着环境压力的降低而增加,但以牺牲流动稳定性为...以西昌钢钒200 t RH-KTB真空精炼装置为原型,借助CFD数值模拟的方法,通过分析射流马赫数、射流动压和半射流宽度,研究了常压及真空条件下超音速氧气射流的特性。研究结果表明:射流马赫数随着环境压力的降低而增加,但以牺牲流动稳定性为代价;尽管存在“流动不稳定”的情况,但适当降低环境压力至10000 Pa有助于减小半射流宽度;当环境压力降至1000 Pa时,射流变得非常不稳定,膨胀严重不足会使流动在0.9 m处出现真空断层。展开更多
文摘用顶吹 CO2 - Na OH溶液体系模拟了 RH- KTB顶吹氧溶氧过程。通过对碱液吸收 CO2 反应动力学的研究 ,考察了操作参数对 RH- KTB顶吹氧脱碳过程中溶氧反应的影响。结果表明 :提高气相中氧分压、增加提升氩气流量或采用低枪位喷吹都有利于加速溶氧脱碳。实验中还发现 :顶吹氧气流量对容积传质系数影响很小 。
文摘The flow and mixing characteristics of molten steel during the vacuum circulation refining, including RH(Ruhrstahl Heraeus) and RH KTB(Ruhrstahl Heraeus Kawasaki top blowing) processes, were investigated on a 1/5 linear scale water model of a 90 t multifunction RH degasser. The circulation rate was directly and more accurately determined, using a new method by which the more reliable results can be obtained. The fluid flow pattern and flow field in the ladle were demonstrated, observed and analyzed. The mixing time of liquid in the ladle was measured using electrical conductivity method. The residence time distribution in the RH model was obtained by tracer response technique. The influence of the main technological and geometric factors, including the gas top blowing (KTB) operation, was examined. The results indicated that the circulation rate of molten steel in the RH degasser can be fairly precisely calculated by the formula: Q lp =0.0333 Q 0.26 g D 0.69 u D 0.80 d(t/min), where Q g-the lifting gas flow rate (NL/min); D u and D d-the inner diameters of the up and down snorkels (cm), respectively. The maximum value of circulation rate of molten steel in the case of the 30 cm diameters either of the up and down snorkels for the RH degasser (the “saturated” rate) is approximately 31 t/min. The corresponding gas flow rate is 900 NL/min. Blowing gas into the vacuum chamber through the top lance like KTB operation does not markedly influence the circulatory flow and mixing characteristics of the RH process under the conditions of the present work. There exist a major loop and a large number of small vortices and eddies in the ladle during the RH refining process. A liquid liquid two phase flow is formed between the descending stream from the down snorkel and the liquid around the stream. All of these flow situation and pattern will strongly influence and determine the mixing and mass transfer in the ladle during the refining. The correlation between the mixing time and the stirring energy density is τ m∝ε -0.50 for the RH degasser. The mixing time rapidly shortens with an increase in the lifting gas flowrate. At a same gas flow rate, the mixing times with the up and down snorkel diameters either of 6 and 7 cm are essentially same. The 30 cm diameters either of the up and down snorkels for the RH degasser would be reasonable. The concentration time curve showed that three circulation cycles are at least needed for complete mixing of the liquid steel in the RH degasser.
