The boiler pressure parts are designed in accordance with accepted European norms and standards. This applies to the selection of materials, calculations of wall thicknesses, production, and certification of welders as well as quality assurance of the finished product.
The furnace is tall and slim in order to obtain a long residence time and good turbulence resulting in good mixing of unburned gases and combustion air. This ensures efficient combustion with low emissions.
A tall furnace also ensures good circulation of water and steam in the panel walls.
Minimal refractory is used in the furnace to prevent ash deposits and slag formation.
From the furnace, the flue gas flows into the upper part of the radiation pass and continues towards the superheater passes, passing a bottom hopper and allowing coarse ash particles to be separated from the flue gas. The collected particles, containing unburnt material, are re-injected into the furnace.
The superheaters are arranged to allow flue gas and ash particles enough time to be cooled below the ash melting point before inlet to the superheaters and to allow ash particles to fall freely down through the heating surface.
The economiser is placed as a separate unit and is provided with heating surfaces consisting of plain or finned tubes.