“An Important Step to Further Boost our Performance”

“Yes, we have come a long way,” says Manuel Delgado, Mill Manager, Papeleira Coreboard. “We believe our success here comes from our ability to keep our customers happy, but also our employees and all the other entities we work with. Our goal has always been to be recognized in the markets as a highly competitive company in the packaging business, with excellent performance in every area. Our experience in the market and the know-how of our team allow us to understand what the market needs – we have a clear picture of our future and of what it takes to get there.” 

THE LATEST ADVANCED TECHNOLOGY FOR LC PULPING

As part of its plan to increase efficiency at the mill, Papeleira Coreboard decided in October 2019 to invest in the latest LC pulping technology from ANDRITZ to replace its two old pulping systems. “At that time, we were managing the pulping process on two lines with heavily used equipment that needed frequent maintenance,” says Delgado. “Between pulper batches there was a lot of downtime necessary for the removal of rejects. In addition, we had problems with handling of the wet rejects that were pulled out.

Can you share details about the hood and air system and what sets the ANDRITZ PrimeLine TAD concept apart from competitors?

JOSEPH GUADAGNO: The process air system is used to transport hot air through the paper sheet with a uniform temperature and pressure profile. There are different ways to properly mix the air and optimize the supply air temperature and pressure profile uniformity to the TAD drum. For this purpose, we developed specially designed static mixers, guide vanes and perforated screens that are incorporated into the ductwork and the TAD supply hoods.

The process air is transported through the large insulated ductwork by the variable speed supply fans that deliver the required air mass to the sheet. A natural gas-fired burner is installed after each TAD supply fan to heat the air supplied to the sheet and to increase its drying potential. The supply air ducts are connected to the TAD hood modules with articulating joints that permit the TAD hoods to retract, allowing access during fabric change, sheet breaks, or cleaning and inspections during maintenance shutdowns.

The wet and dry end TAD hoods are constructed of two independent, retractable halves, with perforated nozzle plates that allow proper airflow distribution into the space between the TAD hood and TAD drum. The supply air is “pulled through” the sheet by negative pressure within the TAD drum.

Moisture removed from the sheet is then partially evacuated to the atmosphere using the TAD exhaust fan. The air exhausted to the atmosphere is replaced with fresh air make-up. The TAD supply fan pushes the TAD return air back into the pre-dryer supply air duct system in this continuous drying cycle.

Thus, controlling the TAD supply air properties like mass flow, temperature, and absolute humidity, we optimize the drying capacity of the system. With the proper control of exhaust air pressure, moisture, and temperature, the optimal energy use can be achieved together with extended life of your TAD fabrics, both which represent a significant operating cost.

Of course, various types of heat recovery can be implemented to reduce overall energy consumption. Our goal is to make the highest quality tissue and towel products with reduced energy input.

Our existing equipment created a bottleneck in production, and we had an issue with maintaining the feed to the paper machine. We decided that the only way to solve these problems was to install a new, state-of-the-art line.”

Papeleira Coreboard chose ANDRITZ for the project to replace the mill’s two outdated pulping systems with a new, continuous LC pulping system to solve the efficiency problems, to improve reject handling as well as to save on operating costs. The order contained a complete package, comprising the entire LC pulping system, engineering work, order execution as well as supervision of installation and start-up.

Delgado states, “We are great believers in the fact that we have to work with the right partners if we want to be the best player. We were very confident right from the start that ANDRITZ was the right partner to deliver the complete package for this project.”

The new LC pulping system is an integrated part of an OCC line processing recovered, corrugated containers from the local area (LOCC), with a reject content of up to 10% and designed to produce the mill’s different grades of board.

Thomas Ferk, Product Manager for pulping systems in the ANDRITZ Paper, Fiber and Recycling Division, explains: “The new LC pulping system ordered by Papeleira Coreboard features several design upgrades, including a FibreSolve FSR pulper with new rotor design for efficient slushing and operation at low energy consumption that also reduces the number of pulper rag breaks. Part of the supply is the new pulper hood design that enables fast removal of pulper rags, reduces downtime, and provides a safe ‘steam- and dust-free’ working environment.”

Other advanced features added to the new system include the latest ANDRITZ TrashTrap, which ensures reliable separation and removal of heavy and light rejects. Thus, the new TrashTrap makes operation of the subsequent detrashing system and the entire LC pulping process more stable and contributes significantly towards ensuring higher availability. A state-of-the-art ragger was also installed, allowing superior forming, handling and removal of pulper rags, particularly when combined with the new pulper rotor design and ragger speed control.

KNOW-HOW PUT TO THE TEST

Delivery and installation of all the equipment were both supervised by ANDRITZ and completed by the end of November 2020. However, COVID-19 had created a very serious situation in Portugal at the start of 2021, which meant that no ANDRITZ personnel could be on hand for start-up of the LC pulping system early February. As a result, the extensive know-how of the mill team at Papeleira Coreboard and of the ANDRITZ experts working remotely from Graz was put firmly to the test during start-up.

“We are very proud and amazed at how well the start-up went without any ANDRITZ personnel actually on the mill site,” says Delgado. “Using video imaging and utilizing remote technology, our own experts were connected with ANDRITZ experts in real time and the whole operation went very smoothly. It was a great example of teamwork on both sides.” 

“Added to this, ANDRITZ had access through our DCS system, which was very important in allowing all the activities during and after start-up to be monitored. There are definitely huge advantages in using this remote way of working, both during such challenges as the pandemic but also in the future, as it could greatly reduce the cost of such operations and activities.”

Klaus-Peter Janisch, Director of Order Execution, ANDRITZ Paper, Fiber and Recycling Division, says, “This very successful start-up was only possible due to the excellent know-how and experience of the mill team. We were very fortunate to have such knowledgeable people on the mill site during this start-up.”   

FROM BOTTLENECK TO ADVANTAGE

Drawing a general conclusion, Delgado says, “We now see a great improvement in our stock preparation – better handling of raw material and rejects and increased reliability. Since start-up of the new line, the maintenance work needed has dropped by 60% compared to the old lines. We also have more flexibility now in using varied and challenging furnishes. All in all, this project was an important step to further boost our performance.”