APC - HF Alkylation
Specific Application for HF Alkylation Units
The HF Alkylation advanced control package uses Axens' latest generation multivariable controller MVAC.
It is designed to maximize the benefits from the HF Alkylation process in an environment with difficult and particularly slow, multivariable interactions.
A six-step control strategy is implemented
- Reaction section control:
- isobutane/olefin ratio maximization,
- maximum reactor temperature,
- maximum reactor inlet pressure
- iC4 recycle composition control:
- nC4 content,
- C3 content, by adjusting the C3 purge flow
- iC4 inventory control, by adjusting iC4 make-up, to maintain the level of the iC4 surge vessel
- Iso-stripper fractionation control by adjusting reboiling power and saturated feed flow
- Olefinic feed maximization, subject to unit constraints
- Alkylate RVP control
Feed drums level control can also be included in the APC strategy.
- Reduction of iC4 losses ( - 40 % )
- Reduction of iC4 import ( - 60 % )
- Increased Alkylate production ( + 3 % )
- Improvement of operational stability
- Safe protection of reactor constraints
- Reduction of the complexity of operator workload