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1.
通过采用商业软件Fluent12.1建立了大型石油焦回转窑窑内煅烧过程三维数值模拟模型,获得了在正常操作状态下窑内温度场、流场和物质浓度场的分布状况。计算结果显示,由于窑尾变径的影响,窑尾气流速加快,影响石油焦粉料的带出;窑内石油焦的升温速度较快,导致挥发分在靠近窑尾段大量析出,窑尾温度偏高,大量挥发分没有及时在窑内完全燃烧;由于窑头漏风的影响,造成煅烧带炭质烧损的增加。  相似文献   

2.
《轻金属》1977,(5)
我厂生产氧化铝的生料浆,系采用喷入法以高压机械雾化喷枪送入回转窑内。长期以来,料浆的计量和喂料量的稳定,被认为是个老大难问题。由于我厂采用的料浆碱浓度高,流动性差,料浆中石子、铁屑、纤维等夹杂物  相似文献   

3.
建立了SO2、HCl酸性烟气喷雾干燥净化的气相、颗粒相及传热传质数学模型,模拟了浆滴运行参数对酸性烟气净化的影响,研究了浆滴在塔内的位移随入口烟气速度的关系;实验分析了雾化加湿和浆滴浓度对烟气净化效率的影响.实验结果表明:喷雾干燥过程中加入雾化加湿水后,SO2、HCl的脱除效率都增加,SO2脱除效率增加明显;增加浆液浓度,SO2脱除率和HCl脱除率均略有下降,且SO2脱除率减小程度大于HCl.模拟结果表明:当入口烟气速度为5 m/s时,浆滴的位移范围较大;随着浆滴粒径的增加,浆滴的温度随着时间逐渐升高,30,60和9 0 μm粒径的浆滴温度分别在3,3,4 s时达到稳定;随着浆滴粒径的增加,脱除效率不断增加,30,60和90 μm粒径条件下 HCl的去除效率分别在1.5,1.7和2 s达到平衡,SO2的去除效率分别在2.5,3.5和4 s达到平衡,可以看出, HCl 与SO2相比,其达到最大脱除效率的时间更短;随着入口烟气温度升高,SO2和HCl的脱除效率都在增大,HCl脱除效率比SO2脱除效率达到稳定的时间更短.  相似文献   

4.
在不同温度和苛性碱浓度条件下研究了亚油酸对铝酸钠溶液加晶种分解附聚过程的影响.结果表明,少量亚油酸能轻微提高铝酸钠溶液的分解率,但能显著增加产品平均粒度.较之空白实验,添加量为4mg/L时,8h使分解率增加O.22%,使产品平均粒径增加8μm;添加量为200mg/L时,8h使分解率降低5%,使产品平均粒径减小5μm.低温和低苛性碱浓度时亚油酸促进溶液分解,高温和中等苛性碱浓度时,亚油酸促进溶液中细粒子附聚.  相似文献   

5.
建立了回转窑实验装置,通过冷态实验研究了回转窑转速、倾角、内径、窑尾挡料圈高度等操作参数和结构参数对物料停留时间的影响。结果表明,物料在回转窑内的停留时间分布近似正态分布;物料停留时间随着回转窑转速、倾角和内径的增大而缩短;窑尾挡料圈高度对物料停留时间影响较复杂,转速小于2.5 r/min时,窑尾挡料圈高度的增加使物料停留时间延长,而当转速大于2.5 r/min时,窑尾挡料圈高度的增加反而使物料停留时间缩短;在某一固定回转窑倾角时,物料停留时间与物料质量流率的乘积与单位转速内物料质量流率近似成线性关系。  相似文献   

6.
为探究初始料浆温度变化对超细尾砂料浆流变参数的影响及管道内料浆温度分布特征,开展了超细尾砂料浆流变试验,进行了料浆流动传热仿真试验,推导了流变参数预测模型及管输温度分布计算模型。结果表明:料浆温度与超细尾砂料浆屈服应力、塑性黏度均遵循Exponential Decay 2拟合模型;不同料浆初始温度下管径与管道内料浆温度符合Asym2sig拟合模型,将其模型参数与管径进行深度拟合分析,利用管径表示拟合模型中的变化参量,实现了变量的统一;超细尾砂料浆流动时摩擦生热高于水化产热,依据传热学理论,超细尾砂料浆经管道内摩擦产热传热、水化产热传热以及与外界环境交换传热后达到动态平衡;基于流变参数预测模型及管道内温度分布模型,可在已知管径、料浆初始温度条件下预测管道内料浆屈服应力和塑性黏度。  相似文献   

7.
建立了SO_2、HCl酸性烟气喷雾干燥净化的气相、颗粒相及传热传质数学模型,模拟了浆滴运行参数对酸性烟气净化的影响,研究了浆滴在塔内的位移随入口烟气速度的关系;实验分析了雾化加湿和浆滴浓度对烟气净化效率的影响。实验结果表明:喷雾干燥过程中加入雾化加湿水后,SO_2、HCl的脱除效率都增加,SO_2脱除效率增加明显;增加浆液浓度,SO_2脱除率和HCl脱除率均略有下降,且SO_2脱除率减小程度大于HCl。模拟结果表明:当入口烟气速度为5 m/s时,浆滴的位移范围较大;随着浆滴粒径的增加,浆滴的温度随着时间逐渐升高,30,60和9 0μm粒径的浆滴温度分别在3,3,4 s时达到稳定;随着浆滴粒径的增加,脱除效率不断增加,30,60和90μm粒径条件下HCl的去除效率分别在1.5,1.7和2 s达到平衡,SO_2的去除效率分别在2.5,3.5和4 s达到平衡,可以看出,HCl与SO_2相比,其达到最大脱除效率的时间更短;随着入口烟气温度升高,SO_2和HCl的脱除效率都在增大,HCl脱除效率比SO_2脱除效率达到稳定的时间更短。  相似文献   

8.
烧结法生产氧化铝工艺中,A/S是生料浆指标控制的关键。针对传统生料浆生产工艺中料浆A/S控制中的不足,提出了改变硅渣回头方式,以硅渣浆调整为主。调整矿加入为辅的改进方案。大幅度提高生料浆A/S稳定性,并促进了其它各项指标的提高和熟料窑的高产稳定运行。  相似文献   

9.
高碱铝硅酸盐料浆烘干过程特性研究   总被引:1,自引:0,他引:1  
以烧结法生料浆为研究对象,对生料浆烘干过程中的料浆的黏度变化、不同温度条件下料浆烘干速率进行了试验研究。研究结果表明:料浆黏度与料浆钙比关系不大,随温度升高,黏度降低,且在水分38%为黏度变化拐点;烘干过程中,当料浆水分减少到20%左右时,料浆黏度突然降低,成为塑性;烘干过程基本上为恒速干燥,随温度的升高,烘干时间变短。这些结论对铝硅酸盐料浆的烘干有较大的指导意义。  相似文献   

10.
研究不同熔融纺丝轮表面形态,即光滑表面和齿轮结构表面,对液态金属雾化成粉末的影响。研究熔融纺丝过程中轮子转速、气体喷射压力、熔融金属温度、喷嘴-轮子间距等工艺参数和轮子表面形态对6060铝合金粉末及带材的形貌和显微组织特征的影响。结果表明,用光滑轮可得到带状材料,用齿轮可得到粉体。随着工艺参数的变化,用光滑齿轮生产的带材厚度为30~170μm,宽度为4~8 mm;用齿轮生产的粉末平均粒径为161~274μm。提高轮子转速和熔体温度、降低气体喷射压力和喷嘴与砂轮间距导致带材厚度和粉末粒径减小。粉末和带材的显微组织为等轴晶,且平均晶粒尺寸随着带材厚度和粉末粒径的减小而减小。在最大冷却速率为2.00×10~5和1.26×10~4 K/s条件下可分别得到厚度为30μm的带材和粒径为87μm的粉末。  相似文献   

11.
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.  相似文献   

12.
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.  相似文献   

13.
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.  相似文献   

14.
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.  相似文献   

15.
韩磊 《腐蚀与防护》2015,36(1):84-90,94
综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。  相似文献   

16.
Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.  相似文献   

17.
On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes' collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.  相似文献   

18.
The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.  相似文献   

19.
正Harbin General Hydraulic Machinery Works Co.,Ltd.of Yilin Hydraulic Group is the most professional production base of large-scale metallurgy oil cylinder and oil machinery cylinder in the Northeast of China.The main products include metallurgy cylinder,swell-shrink cylinder,rotating injection device,lifting cylinder,main lifting jack,front lifting jack,engineering oil cyl-  相似文献   

20.
<正>Copyright Information For Authors As soon as an article is accepted for publication,authors will be requested to assign copyright of the article(or to grant exclusive publication and dissemination rights)to the publisher(respective the owner if other than Springer).This will ensure the widest possible protection and dissemination of information under copyright laws.More information about copyright regulations for this journal is available at  相似文献   

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