Our highly corrosion-resistant Heat Recovery System allows the extraction of a particular amount of heat from flue gas before entering the flue gas desulfurization system. The decoupled heat is either transferred into the main condensate system through an intermediate water circuit or it is used to reheat the primary air before entering the regenerative air preheater (Ljungströmprinciple).

The cooling procedure assures effective operation of the desulfurization unit. The water losses in the desulphurization system are reduced to a minimum. The flue gas cooler is either connected to a low pressure feed water preheater or the regenerative air preheater. By making use of the extracted heat, the amount of steam used for preheating is significantly reduced. Saving steam used for preheating leads directly to greater efficiency of the power plant. While cooling the flue gases, the acid dew point is reached. To satisfy the strict requirements for chemical resistance, high capability, high reliability and long lifetime, Wallstein developed the so-called AlWaFlon_® tube material. These tubes are based on the filuoropolymer base material of our partners DuPont, Switzerland and Fluortubing, Netherland. Beside corrosion resistance, the Wallstein HRS design has very low maintenance requirements.

Wallstein products are not only beneficial for the power industry because they increase efficiency, they also contribute to the reduction of carbon dioxide emissions. For example, an 830-MW power plant is able to increase efficiency by approximately 1.4% and reduce CO₂ emissions by approximately 100,000 t annually, and save approximately 23 MW of reheating steam.