奧士羅連續結晶系統的設計與控制

Design and Control of Oslo-Krystal Cooling Crystallizer

林敬學(Ching-Hsueh Lin)

指導教授 ： 吳哲夫

國立臺灣大學/工學院/化學工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.00384

摘要

奧士羅冷卻結晶系統由於是連續式的操作，在工業界已有非常長久的應用。蕭立鼎教授在2011年提出該結晶系統的模型(後稱固相分離模型)，該模型可以模擬出指定條件下的濃度散布及結晶粒徑散布。除此之外，藉由作動此模型中各個實驗變數(包括單位時間加入的晶種數目、系統高度、回流比與進料濃度)，可以了解各別實驗變數如何影響最終成品的狀態。藉由此模型，利用Douglas所提出的經驗式計算系統中各個單元的建造成本及營運成本，可以計算出在何種實驗變數的組合之下，能夠以最低的年成本(TAC)達成指定的成品狀態。
除此之外，利用蕭立鼎教授於2001年提出的Batch模型，配合MSMPR模型，可以建立一個和固相分離模型相似的動態模型，為了避免計算上的困難，指定此模型指有單一固相，因此稱之為固相均勻模型。利用此動態模型，可以得到控制變數(成品狀態)對操作變數(任一實驗變數)的動態反應。藉由動態反應得到的系統transfer function，可以利用錢益隆教授與Fruehauf於1990年提出的文章設定控制器參數，藉由作動單位時間加入的晶種數目來確保成品狀態。

關鍵字

結晶 ； 連續式 ； 最適化 ； 動態 ； 控制

並列摘要

An Oslo-Krystal cooling crystallizer is a continuous crystallizer widely used in industry. Shiau and Lu1, [unpublished, 2011]. has proposed a steady state model to simulate the concentration and crystal size profile, also, the effects of each experimental variables (including seed feed rate, total bed height, recycle ratio and fresh feed concentration) to crystal size and concentration distribution are also discussed. By calculating the capital and operation cost of each unit, the optimization in order to minimize the total annual cost is investigated.
Accompanied with the model proposed by Shiau et al.2 [Chem. Eng. Sci., 1999; 54: 865-871]. and the MSMPR (mixed-suspension, mixed-product-removal) crystallizer model by Randolph et al.3 [Academic press, inc., 80-83], a dynamic model called well-mixed solid phase model is developed, the values of each variables at any instance can be derived. Finally, from the dynamic response using the well-mixed solid phase model, a controller is set up to control the crystal size by manipulating seed feed rate. The controller is capable of handling the set point changes of desired product size and the disturbances of fresh feed flow rate and fresh feed concentration.

並列關鍵字

Crystallization ； Continuous ； Optimization ； Dynamic ； Control

參考文獻

1 Shiau L.D. and Lu Y. F., “Modeling of an industrial Oslo-Krystal cooling crystallizer.” ,unpublished, 2011.

2 Shiau L. D. and Lu T. S., “ Interactive effects of particle mixing and segregation on the performance characteristics of a fluidized bed crystallizer “, Ind. Eng. Chem. Res, 2001, 40, 707-713

3 Randolph A. D. and Larson M. A. 1988 “Theory of particulate processes analysis and techniques of continuous crystallization”, Academic press, inc., 80-83

4 Jones A. G. Crystallization process systems: Butterworth-Heinemann; 2002

5 Shiau L. D., Cheng S. H. and Liu Y. C., “Modelling of a fluidized-bed crystallizer operated in a batch mode”, Chemical Engineering Science, 1999, 54, 865-871