Process Automation Recipes Controll and Batch Sequencing in the Polyamide Production
How to grow capacity, increase product quality and optimise productivity? This was the question for the chemical company Arkema on the occasion of implementing a new process control solution for its production lines of ultrafine polyamide powders. The result ist impressive as this case study shows.
The Arkema group is a major international French chemicals manufacturer. From its site at Mont in Pyrénées-Atlantiques, France, it produces a range of ultrafine polyamide powders, known as Orgasol, which are used in the composition of quality cosmetics and in the manufacturing of industrial products such as paints, inks and special or composite paper. Several production lines are used for the manufacture of cosmetic and industrial powders. The instrumentation and control system for these lines is now managed by a Plantpax solution from Rockwell Automation.
Arkema’s decision to extend the production capacity of its Orgasol unit led to the simultaneous renovation of the control system and the deployment of the Plantpax solution. The production equipment was previously controlled by earlier-generation Allen-Bradley controllers but the operations including recipe management, activation of production phases and batch sequencing were handled manually by site operators and could differ between operators. This wasted time during production, particularly for batch sequencing.
Sometimes it is Best to Start Again from Scratch...
Arkema has long been a user of Rockwell Automation solutions. When the company decided to extend and modernise the Automation Control Systems required to manage the new equipment, they looked at newer, more advanced solutions from Rockwell Automation. Philippe Bégards, automation control systems manager for Arkema, explained: “We were satisfied with the control of the Orgasol production lines. Replacing the Allen-Bradley PLC-5s with more up-to-date Allen-Bradley Controllogix systems seemed a satisfactory solution to us; we already used RSView 32 HMI software to monitor the unit and we simply intended to upgrade to a more recent version of this software in the context of the extension of our production resources.”
This is where the Rockwell Automation Global Solutions project team came in. The team proposed a complete rewrite of Arkema’s process approach in parallel to the capacity extension project; an optimised functional breakdown of the process into basic phases, meeting ISA 88 specifications; and the use of the Factorytalk Batch software module within Plantpax for the management of all operations with, in particular, the automatic sequencing of batches for more effective production. Arkema accepted this proposal and the decision was made to go ahead.
The Batch software module manages the production recipes with the necessary flexibility to fit batch production into different lines, where different powder grades lead to substantially different final products.
In January 2007, production at the Mont site stopped for scheduled downtime. The Technical and Global Solutions teams from Rockwell Automation took advantage of this downtime to dismantle the older installation and switch to the new system. According to Christophe Brasseur, Global Solutions project manager, this was a time-critical migration project, as teams only had a two-week window in which to complete the operation. “We were concerned about the batches, and this new means — a revolutionary concept for us — of controlling a production unit,” confided Bégards, who also said that prototype modelling and testing to prepare for the upgrade was an important part of the project.
On the date planned for the restart, the production unit commenced with two lines equipped with 15 % additional equipment and produced two sequenced batches without a single incident. Operators were trained to use the new Batch system during the downtime and managed the new lines without any difficulty.
How to Automate Critical Operations and Steps
All critical production operations for Orgasol (power-up, recipe management, etc.) are handled automatically by Plantpax. “To begin with, we did not really believe it,” states Bégards. “This approach to system control appeared complex. And yet the Batch solution is so well integrated that operations are totally transparent for operators. The system also allows for the flexibility necessary for any modifications and will help us to save time in future upgrades.”
Arkema has never regretted its decision to engage Rockwell Automation. Since the installation of Plantpax, it has increased its production capacity by more than 30 % and is proud of the consistently high production quality. “All our batches are now produced in an identical manner, which has allowed us to achieve unrivalled quality levels for such a complex process, so important in this market,” confirmed Bégards. Arkema’s Orgasol unit can now produce up to six different product batches using the various lines in parallel.