Reduction of fine dust and CO in single room firing systems through two-stage catalyst module

Hand fed log furnaces require an effective and at the same time economically feasible emission reduction in order to comply with future emission limits.

Catalysts integrated in furnaces are a very good and cost-effective way to significantly reduce emissions from incomplete combustion (CO, hydrocarbons). In addition to these gaseous and oxidizable pollutants, however, there is the problem that dusty pollutants are emitted. Up to now, without adaptation and conversion of the firing system, only about 20 % of the dust produced could be reduced by oxidative catalytic decomposition directly at the catalyst.

The new solution from Blue Fire GmbH provides for a two-stage catalyst system. Two catalysts, which are arranged in the furnace in such a way that first the dusty emissions are reduced and then the gaseous parts of the emissions are oxidized. In the first stage, the heavily sooty particles are first retained. In the next step, part of the carbonaceous components are oxidized in stage 1 and then discharged again by the flow from stage 1. This prevents blocking of stage 1. In the second catalyst stage the gaseous pollutants CO and hydrocarbons are reduced.

In order to significantly increase the dust reduction of integrated catalysts in wood firing systems, a two-stage catalyst module developed by Blue Fire GmbH was integrated into a simple wood-burning stove in the lower price segment and tested by the DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH under simulated natural draught conditions. With this two-stage catalyst module the pollutants carbon monoxide (CO) could be reduced by more than 80 %, hydrocarbons (VOC) by up to 70 % and dust by more than 50 %.

The two-stage catalyst module is available and can be integrated into a wide range of different stove models. The measured data are freely available for download at and were presented at the 9th Separator Symposium on 21.03.2018 in Leipzig.