When SCA’s Edet Bruk mill invested in a new burner management system from ABB, the difference was immediate. Two years later, the company tells TW what a difference it has made
SCA’s plant in Lilla Edet, north of Gothenburg, Sweden, has three big paper machines producing tissue paper that eventually becomes household or toilet paper. The manufacturing process involves a headbox pumping a 99%+ pulp-to-water suspension into the machine. The suspension is spread as evenly as possible over the revolving wire as the water is removed and the pulp then goes through a press section to remove more of the water by mechanical means. It is then moved to the drying section or dryer at the end of the process.
On one side of the machine’s big Yankee cylinder (drying cylinder), steam from a boiler is used to dry the tissue paper. On the other side, the hood is filled with hot air. For environmental and safety reasons, two of the paper machines now use natural gas.
To help ensure that the monitoring of this process became more effective, in 2011 Edet Bruk replaced the “black box” that monitored the burners with a new modern burner management system from ABB. The “black box” used to tell the operators only that the dryer was working or not, while the new burner management system responds rapidly with information on why a stoppage has occurred.
ABB developed the function together with Autopro, which sells the software, and which is specially made to integrate the information into ABB’s 800xA-system for full control of the firing process for combustion phases. This has not been possible before and it is a new function that gives the mills safer production. The burner control is useful in, for example, drying machines and in the lime kiln.
Magnus Sultan, automation engineer at Edet Bruk, says: “We have been talking about this kind of solution for many years. For us, it’s about meeting the safety requirements of the authorities and also being able to see what is happening during the process.”
For the paper mill to be able to manage all customer deliveries, production has to be kept running every day of the year, with the machines running at full capacity. Sultan added: “Whatever the reason for the machine stopping, we now get a plain text message indicating what is wrong and we can deal with the fault immediately. The operator is alerted by an alarm, and if they cannot deal with the problem on their own, all they need to do is call the maintenance personnel.”
Previously, ABB did not have a burner monitoring application similar to the new system to offer its customers. The system delivered to the Edet Bruk paper mill has been granted plant approval by DGC (Danish Gas Technology Centre), the Danish certification body. Moreover, by using the documentation that has been produced, ABB is counting on being able to obtain similar approvals for future projects of this kind. “It will mean we can compete on cost with the license costs for the other approved systems already on the market,” says Hans Stenberg, ABB’s account manager.
There are competitors out there that have ready-made solutions that have already been approved. But in spite of that, Edet Bruk opted to have ABB and Autopro develop a version of their own. “Process industries often involve large complex systems where the various units have to be able to ‘talk’ to each other. This is made easier if we opt for solutions from the same ‘family’, and in this part of the plant we do have a lot of equipment from ABB,” Sultan added.
During the first months of operation, Edet Bruk’s investment lived up to expectations. “Natural gas is cleaner than LPG and this means there have been fewer stoppages. And where there have still been stoppages, the operator knows the reason why. But the big benefit for us is that we do not need to devote as many engineer hours to solving problems in the event of a production stoppage.”
By SCA’s automation engineer Magnus Sultan and ABB’s key account manager Hans Stenberg.
