搅拌槽形对含钒页岩固液混合特性的数值模拟

搅拌槽是湿法提钒工业应用的重要设备,但在实际应用中存在矿物混合不均匀、易沉积在搅拌槽底部的问题。运用计算流体动力学(CFD)FLUENT软件,采用多重参考系法（MRF）、标准的k-ε方程、欧拉—欧拉多相流模型,对不同底部形状搅拌槽进行固液流场数值模拟。研究表明,平底搅拌槽对大粒径颗粒易产生固相沉积,圆底搅拌槽能有效解决沉积问题且搅拌更加均匀,槽内搅拌死区大幅下降。对槽内不同位置流场进行考察,圆弧底搅拌槽的湍动能、速度均优于平底搅拌槽,有利于提高固液混合效率。     

油箱壁板裂纹分析

两批油箱壁板在加工完成后,放置一段时间后出现裂纹.通过对故障油箱壁板的裂纹宏观观察、断口的宏微观观察以及裂纹金相分析和材料的性能测试,对壁板裂纹的性质与原因进行了分析.结果表明,两批油箱壁板裂纹的性质均为应力腐蚀开裂,壁板上应力腐蚀裂纹的产生与壁板材料的热处理状态、壁板加工后较高的残余应力以及存放环境中的腐蚀介质有关.     

5000m3液氨球罐缺陷分析

介绍建峰化工总厂化肥厂液氨球罐在进行周检时发现的缺陷及状况。针对不同类型缺陷 ,对其出处、成因按相关标准理论进行详细分析 ,运用规程进行强度校核、评定 ,得出球罐在下一检验周期前仍然安全可靠 ,提出了预防措施和建议     

油罐清洗过程中的安全管理

阐述了油罐在清洗过程中可能出现的各种事故，以及针对各种事故所采取的预防措施，从而从根本上控制油罐清洗过程中安全事故的发生。     

EFFECT OF SUSPENDED FIBRES ON MACRO-MIXING AND MICRO-MIXING IN A STIRRED TANK REACTOR

The effects of suspended fibre on macroscale and microscale mixing in a small stirred tank reactor were studied under batch conditions using the competitive, consecutive azo coupling between 1-naphthol and diazotized sulfanilic acid. The mixing quality was determined from the distribution between the mono and bis substituted reaction products. Nylon (2 and 3 millimeters in length) and fully bleached softwood kraft pulp (FBK) fibre suspensions were examined at volumetric concentrations up to the limit that complete suspension motion could be maintained in the vessel at impellet rotational speeds of 7 and 10s^-1. The adsorption of the product dyes on the fibre was found to be proportional or very nearly proportional to their concentrations in the aqueous phase and did not interfere with the assessment of mixing in the suspension.

Suspended fibres were found to slightly increase the 'critical feed time' of the diazotized sulfanilic acid, corresponding to an increase in the macromixing or bulk blend lime of the vessel. Continued increase in the fibre concentration led to the formation of a well mixed cavern centered on the impeller and the creation of stagnant regions adjacent to the vessel walls. The departure from the Newtonian fibre-free case is due to changes in the flow through and distribution of the energy dissipative regions in the vessel. The most effective location for chemical addition to ensure good microscale mixing remains in the impeller vicinity.     

改进马蹄焰玻璃窑炉加料口设计的体会

我厂总结加料实际运行情况,分析加料口对配合料熔化作业的影响,在仍采用一台(嘴宽为800mm)毯式推料加料机情况下,对24m~2的马蹄焰熔炉加料口结构进行了改进,取得了较好的效果。     

Biological treatment of wastewater from a polymer coating process

Wastewater containing propylene glycol methyl ether from a powder and E‐coating plant was treated biologically. The wastewater was circulated through a packed column at rates of 0.014, 0.028, and 0.042 m³ m^?2 s^?1 (14, 28, and 42 kg m^?2 s^?1) with an airflow in a countercurrent direction. Various air flowrates from 0.034 to 0.10 m³ m^?2 s^?1 (0.041–0.12 kg m^?2 s^?1) were used. The removal of the biological oxygen demand (BOD) of the wastewater did not change significantly with the air flowrate. After 4 days of treatment in the packed column the BOD was reduced by about 70% while a BOD reduction of 10% was observed with the wastewater in a stagnant tank. BOD removal with aeration in the packed column was about 40% higher than that without aeration. At the air flowrate of 0.068 m³ m^?2 s^?1 and the liquid flowrate of 0.028 m³ m^?2 s^?1, BOD removal for the wastewater seeded with Polyseed® increased by about 25% compared with that of the unseeded wastewater. In order to minimize the power consumption, cyclic pumping of the liquid to the packed column with aeration was also tested. For the liquid‐pumping cycle of 2‐h on and 4‐h off, BOD removal was about the same as that with a continuously pumping operation. © 2002 Society of Chemical Industry     

突扩突跌掺气设施后泄槽底板脉动压力试验研究

有压洞出口后的突扩突跌掺气减蚀设施在水利工程中经常使用。由于水流受边界条件和掺气的影响,其流态和脉动压力往往与普通水槽的情况有很大的不同。通过水工模型试验,对突扩突跌掺气设施后泄槽底板上的脉动压力进行研究,揭示了掺气设施后泄槽底板上不同流动区域的脉动压力特性。从脉动压力的时域过程、均方根值、偏态系数、峰态系数和主频率等多方面得出冲击区、反射区和稳定区脉动压力的特性是不相同的结论。同一流量时,沿流程底板的时均压力都大于脉动压力的均方根值,在冲击区、反射区和稳定区,脉动压力的均方根值分别是同位置时均压力值的约0.5倍、0.6倍和0.7倍。研究成果可为更好地利用突扩突跌掺气设施提供有益的理论和试验依据。     

多层水平气流带式干燥机的数学模型

根据干燥传质传热学原理和干燥动力学特性，建立了水平气流带式干燥机干燥过程的数学模型。该模型可以预测干燥机合理的通风道高度、带翻转最佳时间和热风风速等。为优化多层带式干燥机的结构或设计新的水平气流带式干燥机提供了理论依据。