Alfred Kullik, Engineering, Mitsubishi HiTec Paper Bielefeld Mill in Germany: “Disc Filter crashes began happening frequently. Our mill experienced three major crashes which caused outages of more than 24 hours each. Secondly, the old disc filter has produced only two qualities – cloudy and clear water. We desired capability for super clear filtrate for shower cleaning water to eliminate a very old clarifier that was vulnerable to disruptions. So, we have been searching for a solution for a single installation that would deliver all three water qualities: cloudy, clear and super clear filtrates. We have a Hedemora® disc filter at the PM1 which has been providing our needs, but the bottle neck has been PM3”. Mr. Kullik was in charge of the PM3 rebuild project.
“GL&V provided a rebuild solution and after the preliminary discussions we decided to realize the project to rebuild the existing BeloitTM 12’6”x 10/20 Polydisc® 3000 disc filter for PM3 white water treatment”, says Mr. Alfred Kullik.
Mitsubishi HiTec Paper Bielefeld is a leading producer of specialty paper located in central Germany. The mill is known for its state-of-art technical expertise developing and manufacturing innovative products. Mitsubishi HiTec Paper Bielefeld GmbH produces 150.000 t/a of specialty papers with two paper machines. Paper brands produced by the mill are Giroform self-copy paper, Jetscript inkjet paper, Thermoscript thermo paper and Supercote label paper.
Over 80% of the specialty papers production is exported. The No. 3 Paper Machine is a 5.800 mm wire width twin wire design equipped with an online coater. The design speed of the paper machine was already 1.200 m/min before the disc filter rebuild. Only the approach flow including the disc filter was not designed for the design speed of the paper machine. GL&V evaluated the Beloit filter and determined the necessary scope for a successful rebuild.
The rebuild resulted in Mitsubishi eliminated a Kofta DAP clarifier once used for the production of super clear water for the paper machine showers. The bow screen was also included for additional protection to assure long fibers will not plug the showers. The rebuild provided additional hydraulic capacity while eliminating half of the discs.
In order to make the modification as cost effective as possible, Mitsubishi and GL&V worked together to plan the outage. GL&V designed and manufactured the new high flow cassette grid sectors, new filtrate valve and wear disc, and the new feed box specifically to suit the existing Bielefeld disc filter and to minimize the mill down time. During the outage, GL&V supervised local welders and fitters provided by Mitsubishi. The rebuild was completed during a 120 hours machine stop under GL&V supervision.
“Operators are not speaking any more of disc filter failures”
“The construction and quality of filtrates have been fine after initial challenges as it is always in new installations like this. However we received great support from GL&V through the whole project. Now the disc filter works fine because the operators are not speaking about it anymore. Our installation serves all the purposes we wanted,” says Mr. Alfred Kullik.
“Everything is running well from the very beginning because we got such a good support from the very beginning. We were very pleased over the project management and for all the engineering help working together with GL&V,” says Peter Fink, who has been working as a consultant for Mitsubishi Bielefeld Mill.
“In the former disc filter we have had to repair the plastic segment due to the cracks and other issues in the process. When the operators noticed the problems they have had to shut down the paper machine. That costs a lot of time and money but the most critical is that our customer is not turning to other product providers,” ads Mr. Alfred Kullik from Mitsubishi HiTec Mill Bielefeld.
Dr. Jens Magenheimer, GL&V: “The main question from the very beginning of the project was to replace the complete disc filter against a new one or to reconstruct the existing one. However, I can see that we could convince the Mitsubishi management to turn to the rebuild which costs half of the price of a totally new disc filter. The major “reason why” is that GL&V provides into these types of cases totally improved technology.”
“That’s right. Payback time was a very important factor in deciding the project and generally all projects need to payback between 1.3 and 1.6 years. Now we have saved a small amount of energy by shutting down the Krofta. The white water capacity of the disc filter has been improved and this along with some other modifications at the paper machine has enabled us to increase the machine speed and capacity. After the rebuild of the disc filter we are able to run 1.200 m/min safety!” states Mr. Alfred Kullik from Mitsubishi HiTec Paper Bielefeld Mill in Germany.