الصفحات

Alexandria Engineeing Libraries

بحث هذه المدونة الإلكترونية

شرح طريقة تحميل الامتحانات من المدونة

الثلاثاء، 5 أغسطس، 2014

Modeling and Simulation of a Distillation Unit

Title: Modeling and Simulation of a Distillation Unit.
Author        : Ahmed Yehia Ibrahim Abd El-Kader
Collection   : M.Sc. Chemical
Abstract:
The methanol production process is a petrochemical industry that uses distillation process in the purification of the crude Methanol. Emethanex is a Company located in Damietta produces Methanol with 99.9% purity using the distillation as the end process for the methanol production. it consist of three towers : the Topping column separates light ends as carbon dioxide and Methane from the crude Methanol to be used in the process fuel, the Refining column produces about 50% of the Metahnol production, the remain quantity is produced in the third tower named the Recovery column.
A mathematical model on the Recovery column based on some assumptions is developed to calculate some parameters like the liquid flow rates across the tower. The column consists of 74 stages, the reboiler is stage number 1 and the condenser is stage number 74 named NT. Methanol is the light component from the top of the tower, and is separated as product. Water is the heavy component. It is separated at the bottom to be used in other unit of the process.
The comparing between the plant data and the Matlab calculated values shows a deviation less than 10% for the liquid flow rates across the tower. The model takes into consideration the dynamic equations.
A simulation is done by HYSYS for the three towers in the steady state mode and the dynamic mode. the steady state simulation shows the severe effect of the changing in the rebolier duty in the composition of the streams, for example: increasing of the reboiler duty from 1.900E+07 to 2.460E+07 increases the mole fraction of the Methanol in top from 0.5251 to 0.7645 in the Topping column, also the increasing of the reboiler duty from 2.574E+08 to 2.974E+08 decreases the mole fraction of the methanol in product from 0.9896to 0.6410 in the Refining column. This means that the product is out of specifications. Also the steady state simulation shows the great effect of the reflux rate on the product purity; the decreasing of the reflux rate of the refining column from 2.500E+05 kg/h to 2.200E+05 kg/h decreases the mole fraction of the product methanol from 0.9372 to 0.6347.
The dynamic mode shows that the severe change in the process parameters in controllers makes a big disturbance in the process, for example Changing the set point of the TICRecovery controller that adjusts the Recovery bottom temperature suddenly from 118 °C to 145 °C makes a big trouble shooting and disturbance in the process, the controller returns to the normal operation after 67 min, this is unacceptable in the real process, the dynamic mode shows also the controllers response in normal operation, some studies are created in the dynamic mode, for example the increasing of the bottom temperature of the Topping from 85oC to 90 oC increases mole fraction of the top methanol from 0.591642 to 0.7449, this means that we lose product in the first tower. Other studies are done on the dynamic mode.

ليست هناك تعليقات:

إرسال تعليق