Successful retrofit project at the Sappi plant in Ehingen
In retrofitting projects, companies in the paper industry generally pursue several goals: the renewal of plant technology, the conversion to a different product range, increasing productivity, energy efficiency measures, the improvement of the climate-related production conditions and the reduction of environmental pollution. For a project in Ehingen in southern Germany, the Sappi Group focused on several of these points – and brought a competent specialist for retrofit projects on board in the shape of airinotec. The engineers developed a customized, forward-looking concept for the ventilation of the hall and machinery at the location.
Equipping the Ehingen site for the future
At its Ehingen site, Sappi manufactures chlorine-free sulfite pulp from beech and spruce wood. At the start of the project, the team, which consisted of members of the Sappi team and the engineers from airinotec, defined the goals. The retrofit measures were then divided into two project strands: the bleaching plant and the PM6 paper machine. The measures in the bleaching plant focused on people: Both the climate-related production conditions and an enhanced level of sound insulation were to be optimized. The topic of sustainability was also the subject of the retrofitting work. Different objectives were also envisaged with regard to the paper machine: on the one hand, the goal was to improve the sound insulation, and on the other hand, the potential to save energy was to be taken advantage of as well.
Completing the project with the least possible operational impact
The goals defined for the bleach plant were implemented by airinotec in a variety of steps. The basic idea was to use the waste heat from the paper machine for the heating. For this purpose, the hall supply air units with the duct system were replaced and increased to a capacity of 240,000 m³/h. Analogous to the supply air, the hall exhaust air systems were also renewed and increased to 300,000 m³/h. The connection to the existing PCS7 process control system was made via IO systems from Siemens (ET 200) – and the EnergyOpt energy optimization software from airinotec was integrated into the process control system. Despite considerable changes to the building, the electrics and the systems technology, thanks to the excellent cooperation of the project team, the project was able to run smoothly.
In order not to interfere with operations, the conversion of the plant was carried out during the ongoing production. For the second sub-project, the PM6 paper machine, airinotec installed two air-water heat recovery systems with a total capacity of nearly 3 MW. While these two components have the goal of saving energy, a silencer was installed to reduce the noise emissions to the outside. For cleaning work, the silencer is equipped with retractable baffles and the new duct system with maintenance accesses. The pre-assembly took place during the ongoing production. In December 2020, the four-day downtime assembly on PM6 was successfully completed.
Energy efficiency also reduces production costs
The focus on reducing environmental pollution and increasing energy efficiency that airinotec has implemented in Ehingen has many positive attributes – also for the profitability of production. After all, energy efficiency also means lower production costs. With this investment, Sappi has prepared the plant for the future and is also making a positive contribution to environmental protection. The project in Ehingen once again shows that retrofitting projects in the paper industry aren’t just worthwhile for the environment and employees, they are also good for the companies themselves.
