Christian GollmerEmissionsminderung bei der vollständigen thermochemischen Umwandlung von Holzhackschnitzeln

About this book deutschenglish

The energetic use of woody fuels in combustion plants is associated with the formation of potentially harmful gaseous/particulate emissions. One fuel-related measure - primarily to reduce particulate matter emissions - is fuel-additivation, in which additives are added to the fuel.

For wood pellets, the additive kaolinite/kaolin has proven to be particularly effective in reducing particulate matter. This can incorporate the potassium originating from the wood and normally forming particulate matter as a result of combustion into the ash as high-temperature stable compounds.

Against this background, the aim of this work is to investigate the transferability of the additivation for the reduction of alkali-based particulate matter emissions during the combustion of wood chips. For this purpose, the basic additivation-ability of wood chips is analyzed on a laboratory scale in order to subsequently carry out combustion tests in a commercially available small combustion plant.

For the laboratory tests, kaolin types that differ in particle size distribution or different additives are added to wood chips. Among other things, the potassium recovery sate in the resulting ashes is analyzed for different ashing temperatures. Different types of kaolin are also examined in the combustion tests; similarly, the influence of different additives is also analyzed in more detail here. The analyses include total particulate matter and carbon monoxide emissions. For comparison purposes, an electrostatic precipitator is used as a conventional particulate matter mitigation measure.

The present work shows that fuel-additivation can be transferred to wood chips while complying with the applicable emissions limits. In addition to the selection of suitable additives, the influence of the particle size distribution of the additives used should also be taken into account in the future.