Crude Oil Desalting Using Hydrocyclones

Dilute dispersion/emulsion of ultrafine water droplets containing a variety of salts is usually present in crude oil. It is very useful to remove the water and the dissolved salts, so that corrosion, plugging, and fouling of equipment can be prevented. Electrical desalter is an effective method in crude oil desalting. In order to overcome the shortcomings of electrical desalting system, such as larger equipment volume, complex high tension electricity system, a new process of crude desalting that are based on hydrocyclone technology is designed. Preliminary industrial experiments have been carried out to prove the feasibility of desalting using hydrocyclone. The effects of several dimensionless units, such as Reynolds number, Euler number and pressure drop ratio were studied. An increase in inlet Reynolds number will decrease the pressure drop ratio. With an increase in inlet Reynolds number, Euler number increases gradually. Under the condition that Reynolds number of inlet is ranging from 5000 to 5800, the water concentrations can decrease from 5 vol%  8 vol% to less than 0.40 vol% and the salt concentrations is reduced from less than 8 mg L⁻¹ to 3 mg L⁻¹ after handled.     

Beneficiation of low-grade diasporic bauxite with hydrocyclone

Low-grade diasporic bauxite was treated with hydrocyclone of small cone-angle. The effects of apex diameter, feed pressure and feed concentration on separation indexes were tested, and then the separation process was discussed by hydrokinetics tentatively. The results show that the increase of apex diameter changes the spacial locality of the envelope of zero vertical velocity, resulting in decrease of the ratio of Al2O3/SiO2 in overflow and increase of the recovery of Al2O3 in underflow, while feed pressure and feed concentration have no remarkable effect on the spacial locality of the envelope of zero vertical velocity, however, the separation indexes are improved by the increase of feed pressure, but are worsened by the increase of feed concentration.     

旋流器强化膜组件微滤试验研究

为了分析操作参数对强化过滤的影响并考察膜组件的性能,采用旋流器和PE膜组件结合的方式进行旋流强化研究。试验选用PE管式膜作为过滤元件,采用旋流强化错流过滤方式。影响过滤器过滤的因素主要包括操作参数、过滤物料、过滤环境、过滤介质特性等,通过试验考察了操作参数对过滤通量、过滤精度及过滤周期的影响。试验结果表明,旋流器无溢流管时的强化过滤效果优于有溢流管时的强化效果;随着底流率的增加,过滤的初始通量缓慢增加,过滤的稳定通量下降;随着悬浮液浓度的增加,过滤通量逐渐下降。     

组合式预分离水力旋流器试验

在单体预分离水力旋滤器现场试验获得成功的基础上，对两种不同型式（列管式和筒式）组合预分离水力旋流器的现场性能试验和对比试验结果进行了讨论，重点对筒式组合水力旋流器的分离性能进行了研究。摸索出了较为合理的操作参数（处理量、分流比及压力降等），并对预分离水力旋流器的现场应用工艺流程进行了初步探讨。     

新型水处理装置——动态水力旋流器的试验研究

介绍了新型水处理装置－动态水力旋流器的结构,特点及现场的试验结果,证明其分离效率较了装置高,是工业水处理技术中又一个新的研究发展方向。     

基于CG VOF-DEM和CG Mixture-DEM模型的水力旋流器多相流数值模拟

针对水力旋流器进料固体颗粒的分离过程内部流场复杂,颗粒运动规律难以掌握的问题。本文基于颗粒动力学理论并引入粗颗粒(CG)概念,提出了两种数值模型来对水力旋流器中的多相流进行建模：一种是将多相流(VOF)模型与离散元法(DEM)结合起来的CG VOF-DEM模型;另一种是将混合(Mixture)模型和DEM模型结合起来的CG Mixture-DEM。模拟结果表明,CG VOF-DEM模型在定量上适用于稀疏流,且仅定性地适用于稠密流。另一方面,CG Mixture-DEM模型可以定量地适用于稀疏流和稠密流。研究表明,CG Mixture- DEM模型可以作为评价水力旋流器分离性能的有效工具。     

溢流管结构对三相分离器分离效率的影响

针对柱状气-液-固三相旋流分离器(GLSC)内部复杂的流场分布,借助CFD软件,研究了溢流口处气相体积分数和侧向出口处固相体积分数的分布趋势。通过数值模拟方法,得到了GLSC的气相、固相分布特点,分析了结构参数中溢流管直径Do和溢流管伸入长度Lo对GLSC分离性能的影响。在试验过程中,验证了结构参数的改变对于GLSC分离性能的影响。研究表明,入口流量为1.1m3/h时,该GLSC具有较好的分离效果。     

圆柱型水力旋流器流场CFD软件的数值模拟

借助FLUENT软件,采用RNGκ-ε方程对水力旋流器的流场进行了数值模拟。模拟出圆柱形水力旋流器内部流场的压力分布和速度分布,为研究圆柱型水力旋流器的流场分析提供了理论基础,对其工程实际的应用起到一定的指导作用。     

气体颗粒粒度对气液分离旋流器性能影响的数值模拟

针对一种用于气液两相分离的旋流器结构,采用Fluent软件,开展了分离气体颗粒粒径变化对旋流器压降、湍动能损失特性及脱气效果影响的数值模拟分析。研究结果表明,随着分离气体颗粒粒径增大,旋流器溢流出口的压降先减小后增大,旋流器溢流出口的湍动能损失增大,旋流器气相分离效率逐渐增大。     

Separate Bleaching of Pulp Fractions Enriched in Earlywood and Latewood Fibers

Abstract

Unbleached softwood kraft pulp was fractionated in hydrocyclones into a fine fraction, enriched in earlywood fibers, and a coarse fraction, enriched in latewood fibers. The response to individual bleaching chemicals and the bleachability in bleaching sequences of the pulp fractions was studied.

The light absorption coefficient, light scattering coeffient, and brightness were higher in the unbleached fine fraction than in the coarse fraction. Hydrogen peroxide managed to reduce the light absorption coefficient of the earlywood enriched fine fraction more efficiently than that of the latewood enriched fraction.

In the TCF‐sequence the light absorption coefficient of the fine fraction was reduced to the level of the coarse fraction at a given consumption of bleaching chemicals. In the ECF‐sequence the difference in light absorption coefficient remained between the fractions. At a given consumption of bleaching chemicals, the fine fraction had higher brightness than the coarse fraction, 2%‐ and 1%‐units on the ISO‐scale in the TCF and ECF bleaching sequence, respectively.