Nov 28, 2011. /Lesprom Network/. As part of a comprehensive concept to improve energy efficiency, Papierfabrik Scheufelen is replacing the heat exchanger on its PM5 paper machine. The existing single-stage exhaust air heat exchanger on the hood drier is being replaced by a more effective two-stage air-air and air-water heat exchanger. This single measure represents an investment of around Euro 750,000, yet Scheufelen will recover this in less than one year. Specialists from Finland's EV Group are supervising this investment project, including the implementation phase at the Scheufelen plant at the end of 2011, as the company said in a press release received by Lesprom Network. The new heat exchanger with a total thermal output of 2.8 megawatts is based on a two-stage principle. In the air-air section, exhaust heat warms the newly introduced external air, for example from five to 48°C. In the air-water heat exchanger, meanwhile, exhaust heat is used to heat the process water – which includes a proportion of fresh water and is recirculated in a virtually closed circuit – from around 37 to 55°C. The drying process alone accounts for more than 70% of total production energy consumption in paper manufacturing. At temperatures of around 110°C, more than 1,000 kilowatt-hours of steam is needed to dry one tonne of paper. The more heat that can be channelled back through the air and water exchanges into the production operation, the lower the conventional energy requirements. The new stainless steel tower designed specifically for Scheufelen is roughly 15 metres high and weighs just under 14 tonnes. It will stand just outside the production hall where the PM5 is located. Whereas the previous technology used glass tubes encased in steel for the exhaust air, a stainless steel lattice structure now ensures high heat exchanger efficiency. “Scheufelen is fully committed to improving energy efficiency. The company will therefore continue to make full use of potential energy savings. The aim of these measures is to safeguard jobs and the company as a whole by continuing to offer a competitive priceperformance ratio,” says PL5 Production Manager Dr. Jurgen Hockel on the subject of Scheufelen's investment in the new two stage heat exchanger.