Case Study - Climate change
Closing loops with residual steam
In the past, Smurfit Kappa Roermond Papier in the Netherlands optimised the energy system for each paper machine. Now, an integrated steam-recycling system has been implemented which optimises energy usage throughout the mill. Two large paper machines deliver residual steam to the smaller PM2, through a smart combination of pipes and process control. In the paper-making process, steam is brought into the drying cylinders to dry the paper web. At the other end, residual steam, also called flash steam, and condensate leave the cylinders. Previously, the residual steam of the two biggest paper machines was only partially reused. The energy of the excess steam was converted into condensate. PM2, the smallest machine, has no excess steam – after drying, only condensate leaves this machine. All condensate is sent back to the power plant and is turned back into steam.
Process engineer Wim Janssen devised a residual steam-recycling system. The volume of the residual steam leaving PM1 and PM3 is more than enough for the PM2. This results in less natural gas consumption at the steam boiler, reducing the mill’s CO2 emissions. ‘It sounds simple, but it required in-depth analysis of our processes, and sophisticated process control,to realise a system that also took into account possible downtime of machines, fluctuations in steam production due to changes in paper grades, and the various steam groups within the machines’, says Energy and Sustainability Manager Claire Schreurs.
We believe that new ideas come from collaboration, creativity and having an open mind to view our processes from new angles’, she continues. ‘We are always looking to reduce costs and minimise our CO2 emissions. As a result of closing our loops with residual steam we now annually save over 1.9 million m3 of natural gas and have reduced our CO2 footprint by more than 1,600 tonnes per year. Our success was rewarded with a Sustainability Award in 2017, when we won the first prize in category Process Improvement during the Smurfit Kappa Innovation Event.’