At the beginning of December, Stadtwerke Gießen (SWG) commissioned the first part of the new thermal residue treatment and energy utilisation plant (TREA 2). Since then, the two combined heat and power units (CHP) have been running. They will later provide the necessary temperature increase to drive the power plant's steam turbine set. "The temperature generated during the incineration of the medium-calorific waste is not sufficient for this. With the two CHP units, we have found a solution to this problem," explains Matthias Fink, Head of the Heat Supply Department at SWG.
After the two units had already been in trial operation for a few days, the next milestone was scheduled for 16 December - the pressure test for the boiler of the solid fuel line.
Test with double the pressure
During the construction of TREA 2, the boiler was assembled in Giessen. The manufacturer, Baumgarte Boiler Systems GmbH, delivered this important part of the plant in individual components and assembled it on site from May this year with around 400 weld seams. "Only the pressure test will show whether the boiler remains tight and stable. An exciting moment. We are all the more pleased that this was successfully passed and that TÜV Rheinland was able to issue the test certificate," explains Matthias Fink, comparing this milestone to the topping-out ceremony for a house.
The figures illustrate just how much force the boiler had to withstand during the test: While a pressure of around 42 bar prevails during regular operation, the TÜV approval took place at more than twice this pressure.