Automation and Control of
Mass blending fertilizer plant for SASOL Nitro

In 2007 SASOL Nitro underwent a major plant rebuild of their fertilizer mass blending plant in Cape Town. Due to the nature of corrosion the old plant had to be broken down and a new plant was manufactured for which SK Technologies designed and installed a fully automated PLC and SCADA control system which included detailed reporting of calibrations done on the plant was well as job reports linked the their customers orders.

PLC Software development was done on the 2^nd processors for each servo drive running CT-Net comms between them. The processors was the SM-Applications modules from Control techniques which fully complies to IEC 61131 standard. The master drive in the system was the link to the SCADA via ethernet OPC comms.

The control off the augers that was on the raw material bins was done via servo motors with extra encoder feedback mounted directly on the auger screw.

Mass blends was achieved in excess of 150 Tons with accuracy of 0.05%. Automatic bridging detection was incorporated within the software for each servo to achieve the accuracy.

It was crucial to also have raw material fall on the transfer conveyor belt from each bin at the exact moment to ensure an even blend ratio as per setup recipe.