Gas power plants, which supply electricity to meet peak demands, must work reliably and come online rapidly, especially in the cold times of the year.
For combustion, gas turbines need air that must be free from dust and other particles; consequently, the air is always prefiltered. In the winter months, cold, moist intake air can lead to icing up of the filters. This means that less air is passed through the filters, so the turbines must be choked or switched off - just when they are most needed.
At Trianel in Hamm, Germany, infrared systems from Heraeus Noblelight complement the deicing protection in a modern combined cycle power plant (GuD). Trianel GmbH is a co-operative of 47 public utilities that operates a combined cycle power plant with two block unit power stations in Hamm. Two relatively hard winters over the last two years caused Trianel to consider enhancing its existing anti-icing systems. Any solution had to be as easy as possible to retrofit and very responsive.
Thomas Kleinwaechter, manager of technical management and maintenance in Hamm, met with Heraeus Noblelight to investigate the suitability of electrical infrared systems for this application.
As with most gas power plants, the plant in Hamm used waste heat from electricity generation for filter deicing. The hot air is blown onto the pocket filters, which are made of fleecy material. However, there can be local cold and hot zones, especially when the hot air is not distributed sufficiently.
In contrast to using only waste heat, infrared radiation offered significant benefits for filter deicing. Energy is distributed without contact and generates heat within the fleecy filter material itself. In addition, infrared heat is rapidly available and heating is more energy-efficient than many conventional methods.
Though convinced that infrared would alleviate the icing problem, the power station operators alerted Heraeus to other challenges. At the Trianel plant in Hamm, the deicing enhancement system was a turnkey unit that was supplied complete. Moreover, it was not easily accessible.
"We were faced with a real challenge," says Michael Lyhs, project manager at Heraeus Noblelight. "in the end, there was a window of just three weeks for the total electrical and mechanical installation, and this work had to be carried out at heights of 11 to 25 meters [36 to 82 feet]."
Altogether, surface areas of 28.8 by 13.1' (8.8 by 4 m) were each fitted with 24 medium-wave infrared emitters, with a total rated power of 236 kW. Three emitters were grouped and mounted in frames, and these three-heater modules can be controlled by a switchboard or from the main control room.
"The co-operation and collaboration between the power station staff and Heraeus worked so well that the system was up and running in just two weeks," says Lyhs. "I am convinced that the deicing system will meet the challenges of next winter perfectly."