The Study of Methanol Separation Columns Control

Jafar Sadeghi¹ and Mansureh Ahangar²

¹University of Sistan and Baluchestan Iran.

²MA Student of Chemical Engineering, University of Sistan and Baluchestan Iran.

Corresponding author: E-mail: jsadeghi@hamoon.usb.ac.ir

ABSTRACT:

The design, optimization and better control of refinery processes becomes possible via dynamic simulation. In this article, a methanol distillation unit consisting of three columns has been simulated in order to separate methanol from water, dissolved gasses and heavy hydrocarbons in steady and dynamic states by using Aspen Dynamic and Aspen Plus softwares. Morover, the present study investigates, using simulink/matlab software, the effect of variable changes such as methanol concentration of feed and feed flow rate on the performance of the controllers and the rate of purity of the product methanol flow and water in the bottom of the columns. This system has thermal integration property so that the condenser of the second column acts as the reboiler of the third column and these two thermal loads are considered equal in the flow sheeting equation section of the Aspen Plus software. Then, in dynamic environment, by installing level pressure controllers, the flow rate of feed and product for the three columns, the performance of the unit and the purity of the product will be controlled. The number of the stages (trays) of these three columns is high and shows that there is apparently no need to install thermal temperature controller. Whereas by installing a temperature controller for the first and second column and temperature regulation with reboiler Q (thermal load), as well as cascading control of the third column temperature by means of cascade flow controller in the bottom of this column, the results show high degree of seperation of methanol distillation product. The findings of the research also show that, with the increase of feed flow rate, the purity rate of methanol products will increase, while the purity rate of water flow will decrease. In addition, the increase of feed methanol composition is ineffective on the purity of methanol flows but it has increased the rate of water flow purity. Such a good separation, in turn, is the result of temerature controller instalation. Meanwhile, the increase and reduction of the feed stage position of the first column does not affect the purity of the three product flows.

KEYWORDS:

Control; Design; Aspen Dynamic; Temprature controller

Download this article as: 

Copy the following to cite this article: Sadeghi J, Ahangar M. The Study of Methanol Separation Columns Control. Orient J Chem 2012;28(1).

Copy the following to cite this URL: Sadeghi J, Ahangar M. The Study of Methanol Separation Columns Control. Orient J Chem 2012;28(1). Available from: http://www.orientjchem.org/?p=23795