拟薄水铝石工业生产中搅拌反应釜放大研究

摘要/Abstract

摘要： 针对工业生产装置扩能时，搅拌反应釜放大效应影响产品性质的问题，采用计算流体力学(CFD)软件Fluent对NaAlO₂-Al₂(SO₄)₃法生产拟薄水铝石实验室小型反应釜、工业一倍体积反应釜和二倍体积反应釜3种规模的反应釜进行数值模拟。在实验室小型反应釜上考察了物料流变性、宏观混合时间和反应釜高径比的影响，结合试验结果和反应机理分析发现，为获得大孔体积的拟薄水铝石产品，反应釜中流型需保证加料处的快速混合，并保证加料处的高过饱和度以及釜下部的较低过饱和度。模拟计算结果表明，工业一倍体积反应釜内没有形成加料处强混合和釜下部的局部快速循环，二倍体积反应釜内形成了加料处强混合和釜下部的局部快速循环。工业生产结果表明，二倍体积反应釜所得产品的孔体积优于一倍体积反应釜。进而，在进行四倍体积反应釜的放大时，以二倍体积反应釜的流场特征为基础，通过数值模拟方法对四倍体积反应釜的高径比、搅拌器形状和大小、釜体结构以及挡板安装方式等参数进行优化，计算出四倍体积反应釜及其内构件的尺寸，并据此设计制造了四倍体积反应釜，并在中国石化催化剂有限公司长岭分公司工业装置上进行了工业试验。结果表明，在相同工艺条件下，四倍体积反应釜的产品孔体积与二倍体积反应釜产品的基本相同，解决了反应釜的放大效应问题。

关键词: 拟薄水铝石, 搅拌反应釜, 放大, 孔体积, 放大效应

Abstract: The production of pseudo-boehmite by NaAlO₂-Al₂(SO₄)₃ process is a rapid neutralization reaction, the mass transfer effect of reactants directly affects the product properties, and the structure of stirred reactor influences mass transfer effect. When the production capacity of industrial production is expanded, the amplification effect of stirred reactor becomes the key to affect the product properties. The computational fluid dynamics (CFD) software fluent was used to numerically simulate three kinds of scale reactors: laboratory small reactor, industrial one-volume reactor and double-volume reactor. The effects of rheological properties of the reaction material, macro mixing time and height-diameter ratio of the reactor was investigated on the laboratory small reactor. Combined with the experimental results and the reaction mechanism analysis, it was found that in order to obtain products with larger pore volume, the flow pattern in the reactor should ensure rapid mixing and high super-saturation at the feeding site and low super-saturation at the lower part of the reactor. The simulation results showed that there was no strong mixing at the feeding site and local fast circulation at the bottom of the reactor in the industrial one-volume reactor, while there was strong mixing at the feeding site and fast circulation at the bottom of the reactor in the double-volume reactor. The results of industrial production showed that the pore volume of the product from double-volume reactor was better than that from the one-volume reactor. Therefore, when the reactor was scaled up to quadruple-volume reactor, taking the flow pattern in the quadruple-volume reactor to form the same flow pattern of the double-volume reactor as the objective, the parameters of the quadruple-volume reactor such as the height-diameter ratio, the size of the agitator, the structure of the reactor body and the installation mode of the baffle were optimized by numerical simulation method. The dimensions of the quadruple-volume reactor and its internal components were calculated, the quadruple-volume reactor was designed and manufactured, and the industrial test was carried out on the industrial plant of SINOPEC Catalyst Co. Ltd.,Changling Division. The results showed that the pore volume of the product from quadruple-volume reactor was the same as that from the double-volume reactor under the same process conditions, which successfully avoided the scale-up effect of the reactor.

Key words: pseudo-boehmite, stirred reactor, scale-up, pore volume, amplification effect

曾双亲陈杰梁维军桑小义肖成武杨清河聂红. 拟薄水铝石工业生产中搅拌反应釜放大研究[J]. 石油炼制与化工, 2023, 54(7): 1-9.

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