APC - Prime-D

Specific Application for Prime-D

The Prime-D advanced control package combines Axens Horizon' 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 Horizon combines all the necessary expertise for successful Prime-D APC projects.

A six-step control strategy is implemented

• 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

• for a new feed, determination of new MV targets, using the reactor model
• rapid ramping to new targets, with constraint protection and sulfur control

Precise sulfur control

• the Prime-D control package uses Axens Horizon' on-line ULSD reactor models to estimate the sulfur content of the product at the reactor outlet.
• this technology allows precise sulfur control and fast feed switchover, even when the 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

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)