用于泡沫混凝土制备的静态混合器模拟研究

泡沫混凝土作为新兴的轻质绿色建材近10年来发展迅速,具有广阔的应用前景。在泡沫混凝土的制备工艺中,浆体搅拌与泡沫混合环节是决定泡沫混凝土性能的关键因素。但“重发泡,轻混泡”的问题长久存在,混泡工艺的理论研究和设备发展都有所欠缺。因此,设计一种符合泡沫混凝土物料性能,能够实现连续化高效生产的专用混合器非常必要。本工作综合考虑混合器的特性,选用静态混合器作为泡沫混凝土的混合装置,采用数值模拟的方法对泡沫浆体混合过程进行仿真计算,建立不同结构参数下的静态混合器三维实体模型,分别通过仿真模拟研究元件个数、管道内径、元件夹角和加料口位置等不同参数对水泥浆体和泡沫混合情况的影响。结果表明,当元件的切割作用与流体分布垂直时,更有利于混合;混合器的管内径越小,混合速度越快,密度分布越均匀,但同时设备耗能更高;元件数量与最终产品的混合效果呈正相关;加料管口与混合元件的距离越小,越有利于均匀混合。综上所述,在θ=90°、D=60 mm、n=10、L=20 mm的条件下,最终可以制备出混合均匀、密度为1400 kg/m^(3)的泡沫混凝土。本研究可为新型泡沫混凝土混合装置的研发提供参考和支持。

Solvent extraction of Ce(Ⅲ) and Pr(Ⅲ) with P507 using SiC foam as a static mixer

Extraction reactor is a major research area of interest within the field of rare earths extraction and separation.SiC foam offers excellent material characteristics as well as three-dimensional(3-D) reticulated structure;however,very little research has been carried out on its application in extraction reactor so far.In this work,a static mixer reactor based on SiC foam was designed and demonstrated to extract and separate Ce(Ⅲ) and Pr(Ⅲ) from nitric acid media by using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester(P507) as extractant.The structure-performance relationship between SiC foam and extraction performance was studied by experiment combined with computational fluid dynamics(CFD)simulation.The experiment data are in good agreement with the simulation results.Contrast experiment by using a Kenics mixer was carried out,and SiC foam shows better extraction and mass transfer performance.Using the optimal structural SiC foam(pore size D=2.3 mm,open porosity ε=85%,foam length L=80 mm),high extraction efficiency η(Pr(Ⅲ):94.6%,Ce(Ⅲ):88.5%) and separation factor β(2.27) between Ce(Ⅲ) and Pr(Ⅲ) is achieved at a high total throughput of 200 mL/min.Besides,overall volumetric mass transfer coefficient K_(L)a of Pr(Ⅲ) and Ce(Ⅲ) are 0.519 and 0.378 s^(−1) at the residence time τ of 3.6 s,respectively,which reach the high level of microchannel reactors and are better than conventional extractors and other static mixers.SiC foam is found to be applicable as a static mixer for efficient and high-throughput extraction and separation of rare earths.

一种正压式低倍数泡沫发生装置的研发

开展灭火实验,对比正负压泡沫发生装置的灭火效果。通过泡沫发泡倍数和析液时间等泡沫稳定性测试,优化了正压式泡沫发生装置结构。通过引入SK静态混合器作为扰流装置完成正压同轴混合腔的优化。结果表明,正压式泡沫发生装置灭火效果优于负压式泡沫发生装置;同轴混合腔发出泡沫性能参数优于T型混合腔。通过优化正压发生装置混合腔体结构和扰流装置,提升了低倍数泡沫灭火剂发泡性能参数。

后发泡型透明沐浴凝胶配方及工艺技术的探讨

本文着重探讨后发泡型透明沐浴凝胶。通过单一表面活性剂的测定，得出配方中所需的主表面活性剂。通过正交实验，得出主表面活性剂的含量对产品形成凝胶结构起到比较关键的影响，同时增稠剂以及发泡剂对体系影响也较大。在工艺上采用静态混合方式来达到把发泡剂与料体充分混合均匀，并最终充装出成品。通过各项性能测试，得出发泡剂对于沐浴凝胶的影响较大。