Industrial wood firing – sustainable heat, clean air

Burning wood, wood chips, pellets or residues produces dust and, above all, nitrogen oxides (NOx), carbon monoxide (CO) and unburnt organic compounds. Nitrogen oxides can be reduced with an SCR catalyst and a reducing agent, while CO and organic components are treated with an oxidation catalyst. Dust itself is not removed catalytically but separated by cyclones, fabric filters or electrostatic precipitators. Which combination makes sense depends on the fuel, the combustion technology, the load profile and the requirements in your permit. The temperature window and dust removal are often the deciding factors in the design, because the catalyst must be located at a point in the flue gas path where the temperature is suitable and the dust load is manageable. If you send us the fuel type, the thermal output and a recent emission measurement report, we will assess which catalyst technology is suitable for your plant.

Flue gas from wood and biomass combustion contains fly ash that can block channels and cover active surfaces. Wood ash also contains alkali metals such as potassium, which gradually deactivate SCR catalysts. The most important protection is effective dust removal upstream of the catalyst. In addition, catalysts with a larger cell pitch or plate-type elements are used, as they are less prone to clogging, and cleaning devices such as soot blowers or compressed air pulses are installed. The position in the flue gas path also matters: placing the catalyst downstream of the dust filter relieves it but may require the flue gas to be reheated. During operation, a rising differential pressure is an early sign that deposits are forming. In many cases, fouled elements can be cleaned or regenerated before replacement becomes necessary. Send us details of the fuel, the filter technology and the flue gas temperatures, and we will assess which protective measures make sense for your plant.