Tissue machine rebuild: new Crescent Former and plant to achieve 50% more speed
by: Luca Silvestri - A.Celli Paper
In the tissue industry, the goal of manufacturing is to produce a lightweight and soft sheet of paper that can be converted into a myriad of consumer-ready products. The faster this process can be done, while maintaining product integrity and quality, the better. The crescent former is an integral part in this production, ensuring the stock is properly formed and drained into high-quality paper.
From C-wrap former to Crescent Former
Although the crescent former has been in use since the 1960s, many companies are still using the older C-wrap machines. One such company was one of A.Celli’s customer. As part of A.Celli’s industrial plant retrofits, it was our mission to provide them an upgrade capable of meeting their growing needs. Let’s take a look at their story.
Project’s goals and challenges
Our customer’s issue, as we mentioned before, was that they were still using a C-wrap former. This solution, also known as a twin-wire former, requires the stock to go through two forming fabrics and then move on to the press felt. In contrast to this, the crescent former combines these two steps into one, allowing the stock to pass between the forming fabric and the press felt. This eliminates an entire step in the process, or rather, integrates the formation and drainage, offering the following benefits:
— Lower capital equipment and maintenance costs
— Lower energy cost
— Compact footprint
— Better formation
— Improved lightweight sheet appearance
Our customer wanted to accomplish three important goals, namely:
— Increase machine speed from 1.200 mpm to 1.800 mpm
— Increase plant productivity from 40.000 t/y to 55.000 t/y
— Modernize the existing recycle paper plant to DIP
— The goal was also to use as much of the existing machine components as possible.
Solution: high quality plant and TM upgrade and superior assistance
First of all, A.Celli conducted dedicated surveys of the customer’s existing setup. Thanks to this, our engineers were able to identify what components could be reused or repositioned and which ones would need to be purchased new. Once the survey with the required modifications was completed, all documentation was provided to the customer and acted as one of the key elements for harmonization with the customer’s needs. The A.Celli supply, in this specific case, included:
— TM modification of wet-end, hood, air system and pope reel section
— A new approach flow system
— Complete modification of existing recycle paper plant where A.Celli added elements like pulper, de-inking cell, washer, hot disperger module and clarifier
— Upgrade of the existing equipment, such as the chemical system and reject system
— New components, including the TM drive, motors and MCC for the new equipment
— New pumps, chests, instrumentations, valves, piping, cables, supports and frames for the new equipment
— Engineering work
— Customer service, including installation
When the upgrade was complete, A.Celli’s customer was happy to experience the following:
— The tissue machine reached 1.800 mpm with high efficiency
— Improved product quality
— Improved plant productivity
— Achievement of agreed energy consumption
In other words, the results met all expectations, providing our customer with a more efficient production process to compete in the tissue marketplace.