The HF Alkylation advanced control package uses Axens' latest generation multivariable controller MVAC.

It is designed to maximize the benefits from HF Alkylation process, in an environment with difficult, and specially slow, multivariable interactions.

A five-step control strategy

* Reaction section control :

- isobutane/olefin ratio maximization,
- maximum reactor temperature,
- maximum reactor inlet pressure

* iC4 recycle composition control:

- nC4 content,
- C3 content, by adjustment of 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 fed flow 
* Olefinic feed maximization, subject to unit constraints
* Alkylate RVP control

Feed drums level control, can also be included in the APC strategy.

Benefits

- 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