Air Separation Technology - Sponsored Whitepaper

Achieving high performance process control (HPPC) requires that the control system operate the plant at optimal efciency over the full range of steady state and dynamic conditions. Air separation processes present particular challenges because of their energy intensive nature and demanding production schedules. The HPPC challenges for both cryogenic and adsorption processes are presented, recent applicable research is summarized, and directions for future research are proposed. The value of the operability index to improved HPPC is also presented and discussed. © 2006 Elsevier Ltd. All rights reserved.

Keywords: Air separation; Operability; Advanced control; Model predictive control

Air separation has become a process integral to many manu- facturing processes. The largest markets for oxygen are in pri- mary metals production, chemicals and gasication, clay, glass and concrete products, petroleum reneries, and welding (Air Products, 2005b). The use of medical oxygen is an increasing market. Gaseous nitrogen is used in the chemical and petroleum industries and it is also used extensively by the electronics and metals industries for its inert properties. Liquid nitrogen is used in applications ranging from cryogenic grinding of plastics to food freezing. Argon, the third major component of air, nds uses as an inert material primarily in welding, steelmaking, heat treating, and in the manufacturing processes for electronics. The separation of air into its components is an energy inten- sive process. The companies designing air separation processes have aggressively reduced the required energy to the point that it is possible to sell a truckload of liquid nitrogen for is less than many common consumer products. This surprising result has been accomplished by advances in process design, pro- cess operation, manufacturing approaches and techniques, and improvements in supply chain management. Process designs have increasingly utilized mass and energy integration, sub- stituted more efcient unit operations for less efcient ones, furthered the development of machinery and equipment used in the process, spawned alternatives to cryogenic production for gaseous products, and required the implementation of advanced

E-mail address: vinsondr@airproducts.com.

0098-1354/$ – see front matter © 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.compchemeng.2006.05.038