Hexion carries out production overhaul

Sant’Albano Stura, Italy - Hexion Specialty Chemical has recently upgraded production processes at its Sant’Albano Stura plant in Italy. The project involved moving from systems managed with a pneumatic and, in some respects, antiquated philosophy based on manual intervention, to fully automated systems. This need was especially felt on the powdered polyester resins production line.

The Sant’Albano Stura site is organised into three units respectively involved in the production of melamine/urea formaldehyde condensation resins for the paper industry (Unit A), of coatings resins (Unit B) and, finally, powdered polyester resins (Unit C). The latter unit saw the start of production automation.

This comprises the phase of the introduction of raw materials into the reactors where all the chemical processes and the drainage of the polymer itself are carried out once it has reached the correct degree of polymerisation inside the reactor detected using some specific parameters. The unloading phase is followed by storage in tanks if the product is liquid, or on cooling belts if it is solid. The final stage is packaging and shipment.

The initial step of the plan, carried out in collaboration with Rockwell Automation, took place in 2000 when it was decided to introduce ProcessLogix alongside the pre-existing PLC. Through a series of small subsequent implementations the full automation of four reactors was achieved, today fully managed by the PLC of Rockwell.

Between 2002 and 2003 the (hot and cold) liquid raw material dosage systems were automated and, finally, in 2005 the automation of the methanol distillation column was completed.

At the same time Hexion Specialty Chemicals tested, alongside ProfiBus, the possibility of interlinking the various PLCs (the pre-existing Siemens ones and the new ones from Rockwell) in order to manage the whole plant from a single control point. The positive results obtained during the test phase have laid the foundations for the start of more complex projects aimed at progressive migration towards Rockwell technology for all production control systems.

As well as the main plant of Sant’Albano Stura, the smaller one of Colà di Lazise is today also controlled through Rockwell's ControlLogix systems. All units implemented are second generation and equipped with non-volatile memory.