Optimizing Control of LIquid-Liquid Extraction Columns

液-液萃取是一种重要的分离过程 也是最近新兴技术的关键一步， 有色金属的湿法冶金生产、处理 用于金属回收和危险废物的稀释废物流 铀和钚的消除、提炼和后处理 核燃料循环和核废料管理， 生化分离 这一切都起着重要作用， 传统的分离，如加氢脱硫， 石油工业. 工业规模设备， 液-液萃取包括柱接触器， 连续流搅拌槽。 缺乏测量 柱接触器的技术， 这是因为控制研究数量有限的原因。 过程 无创超声诊断仪的研制 技术在PI的实验室提供了一个机会， 控制萃取过程的新举措。 此外，在原位微型 锡拉丘兹大学开发的相分离装置可以 与浓度测量探头结合使用 (e.g.,光纤、电导率、折射探头等）和 介绍了多变量控制新可能性， 在线优化 这项工作是一种尝试，利用 上述技术用于安全、多变量地控制 在最佳条件下萃取。 此外，这些技术 是第二个目标的推动力， 多变量非线性预测控制算法 最优操作 液-液萃取过程的优化控制策略 列计划的目标是（一）控制 萃取器内的分散相滞留量，（ii）确保 相对于溢流或相转化的安全操作， 和（iii）控制溶质浓度， 最佳提取效率 该过程将被模拟 （i）一阶传递函数的线性模型， 死区时间，以及（ii）种群平衡的非线性模型 方程，包括液滴相互作用的破碎和 聚结 这两种模式都将用于控制 该过程按以下顺序进行： - 分散相的自适应增益调度控制 使用线性模型，目的是显示 超声波技术在控制中的应用 提取过程。 - 分散相的非线性预测控制 应用群体法的无传质滞留量 平衡方程，以证明物理的有用性， 模型 - 分散相的非线性预测控制 含率 在质量传递过程中。 - 多变量非线性预测控制 浓度使用人口平衡方程在一个 扩展配方，包括传质和 浓度的

Liquid-liquid extraction is an important separation process and a key step in recently emerging technologies such as hydrometallurgical production of non-ferrous metals, treatment of dilute waste streams for metal recovery and hazardous waste elimination, refining and reprocessing uranium and plutonium in the nuclear fuel cycle and nuclear waste management, and biochemical separations. It all plays a major role in traditional separation such as hydrodesulfurization in the petroleum industry. Industrial scale equipment for liquid-liquid extraction include column contactors and continuous flow stirred tanks. There is a lack of measuring techniques for column contactors which has been one of the reasons for the limited number of control studies for this process. The development of a noninvasive ultrasonic technique in the PI's laboratory provides the opportunity of a new initiative in the control of the extraction process. Also, in situ miniature phase-separation devices developed at Syracuse University can be used in combination with concentration measuring probes (e.g., fiber optic, conductivity, refraction probes, etc.) and introduce a new possibility for multivariable control and on-line optimization. This work is an attempt to utilize the above techniques for a safe, multivariable control of the extractors at optimal conditions. Further, these techniques are the impetus for the second objective, to develop a multivariable non-linear predictive control algorithm for optimal operation. An optimizing control strategy for liquid-liquid extraction columns is planned with the objectives of (i) controlling the dispersed phase holdup inside the extractor, (ii) ensuring safe operation with respect to flooding or phase inversion, and (iii) controlling the solute concentration to provide optimum extraction efficiency. The process will be modelled by (i) linear models of first order transfer functions with dead time, and (ii) nonlinear models of population balance equations which include droplet interactions of breakage and coalescence. Both models will be applied for the control of the process in the following sequence: - Adaptive gain-scheduling control of the dispersed phase holdup by using linear models, with the objective of showing the application of the ultrasonic technique in the control of the extraction process. - Nonlinear predictive control of the dispersed phase holdup without mass transfer by applying the population balance equations, to demonstrate the usefulness of physical models. - Nonlinear predictive control of the dispersed phase holdup during mass transfer. - Multivariable nonlinear predictive control of holdup and concentration using the population balance equations in an extended formulation to include mass transfer and concentrations.