الفهرس 
INTRODUCTION AND REVIEW OF LITERATUREOnly 14 pages are availabe for public view
 |  | from | 212 |  |  |
| | | from | 212 | | |
Abstract
Cryogenic air separation unit (ASU) is commonly used to produce large quantities of pure oxygen, nitrogen, and argon for many industrial applications. Nowadays, it constitutes an integral part of many industrial processes; it is used in the steel industry to supply the process with oxygen, and in the petrochemical and fertilizers industry to supply the process with nitrogen. It also plays an important role of the new oxygen-fed integrated gasification combined cycle (IGCC) power plant. These applications are subjected to periodic load change, so the ASU units should be characterized by fluctuating operating conditions to respond to the changing of product demand. A complete steady state simulation model of a heat integrated double distillation column of a cryogenic air separation unit is designed. This design includes sufficient optimization calculations to achieve the optimum possible values of the main model parameters. A sufficient control system is installed on the designed model by using simple single input single output (SISO) PI controllers and coupling them between the controlled and manipulated variables. A careful study of tuning of the critical controllers is also proposed. This control system includes also an operation control strategy to give the plant the ability to be operated under different production modes (liquid oxygen, liquid nitrogen, or both) at wide range of partial loads (typically from 100% to 25%). Finally, the performance of the plant under 42 different operation cases has been presented during 24 hours, these cases include different production modes under different partial loads. The simulation of the steady state model was designed by using Aspen-Plus Software, then the dynamic control system was installed by using Aspen-Plus Dynamics software, and finally the results and performance analysis were proposed by using Microsoft Excel software. Results and analysis show that the designed model, with the installed control system, can be operated under wide range of partial loads (100% to 25%) during different production modes while the products qualities are in their allowable ranges.