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Advanced Process Control A Real World Example. Jim English UT Graduate, ChE ‘04 April 27, 2006. Introduction. Who am I? Who is Air Liquide?. Why am I here?. “Real World” example Some notes from industry. So what’s the story?. HyCO = Hydrogen + Carbon Monoxide
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Advanced Process ControlA Real World Example Jim English UT Graduate, ChE ‘04April 27, 2006
Introduction • Who am I? • Who is Air Liquide?
Why am I here? • “Real World” example • Some notes from industry
So what’s the story? • HyCO = Hydrogen + Carbon Monoxide • How does the HyCO work? (Go to PFD) • Amine System (Go to Amine)
Reformer Amine System (Reactions) (Details) HyCO Process Flow Natural Gas + Steam Dryers PSA Cold Box Membranes Hydrogen CO
~60’ Reformer Reactions Natural Gas Reforming: • CH4 + H2O ↔ 3H2 + CO Water Shift Reaction • CO + H2O ↔ H2 + CO2 • Back to PFD
Amine System Process Gas Outlet Amine System CO2 Stripper Absorber Reboiler (Inside) Process Gas Inlet Heat Exchanger
Pictures Inside Top Wall Reboiler Stripper X Re- boiler
Missing Clips Downcomer Tray Pictures Inside Stripper Re- boiler X
Pictures Inside Steam Deflector Plate Stripper Re- boiler X
Form the Team • Research & Development • Engineering & Design • Process Control Experts • Plant Operations • HyCO Personnel
What’s our Goal? • Reduce corrosion in the stripper… • While maintaining absorber’s CO2 removal
But Why? • If we have to replace stripper packing… • $50,000 for packing • Plant shutdown = lost product revenue • Packing degradation ruined2 pumps ($$$)
What’s Important?... • Constraint Variables • Manipulated Variables • Disturbance Variables
Which Allows Us To… CV Target MVPC Controller CV Value MV Setpoint MV History DV History
Amine System Revisited CO2 CV CV Process Gas Outlet Stripper CV Absorber Reboiler MV CV Process Gas Inlet Heat Exchanger DV CV CV MV
MVs CVs How do these guys interact?
Next came the tough part • Test & collect process reaction curves • Import to Excel & Matlab • Fit First Order plus Time Delay models
Example Step Response (0.5) G = 0.5 τ = 4.5 θ = 3.0 θ τ (3.0) (7.5)
MVs CVs Now we Know Modeled Modeled Modeled Modeled Modeled Modeled Modeled Modeled Modeled Modeled Modeled
Post Implementation Overall Results Corrision Temperature • Reduced average temperature by 5°F (225°F to 220°F) • Decreased standard deviation by 60%(10°F to 4°F) Tavg = 225 ± 10°F Tavg = 220 ± 4°F
Miscellaneous • Project Updates • Tools used • Tasks performed
Conclusions • Important Factors: • ENTIRE team • We reduced the risk of corrosion! • Project’s success is leading to further MVPC around the plant’s reformer
Thanks! Questions?