The Prime-D advanced control package combines Axens' latest generation multivariable controller MVAC, in association with on line inferential reactor model and feed switch technology; it is designed to maximize the benefits from Prime-D process at the lowest operating cost.

As process licensor, catalyst manufacturer and advanced control technology supplier, Axens combines all the necessary expertise for successful Prime-D APC projects.

Six-step control strategy

* precise control of sulfur in ultra low sulfur products
* adjustment of hydrogen make-up for optimal H2/HC ratio in the 2 reactor beds
* control of reactor bed outlet temperatures
* catalyst deactivation monitoring
* throuput maximization (under catalyst run length and unit constraints)
* if 2 feed available, maximization of lowest value feed

Feed switch technology

* if new feed, determination of new MV targets, using reactor model
* rapid ramping to new targets, with constraints protection and sulfur control

Precise sulfur control

* the Prime-D control package uses Axens' on-line ULSD reactor models to estimate the sulfur content of the product at reactor outlet.
* this technology allows precise sulfur control and fast feed switch, even when downstream sulfur on-line analyzer has a measurement lag in the order of 2 hours.
* static gains of APC models are updated on-line, for better control

This technology allows precise sulfur control, even when downstream sulfur on-line analyzer has a measurement lag in the order of two hours.

Benefits

* Sulfur on spec without give-away
* Minimization of feed switch time
* Catalyst run length maximization
* Reduction of hydrogen make up
* Minimization of energy consumption
* Increased throughput (if feed available)