WOOD RESEARCH Volume 63, Number 1, 2018
Małgorzata Kajda-Szcześniak and Tomasz J. Jaworski

Characteristics of the combustion process of woodwork waste in the installation of thermal treatment of municipal solid waste (tpok)

The article presents tests concerning efficiency of combustion process in a layer by defining quantitative evaluation indicators (localization of reaction (flame) front, ignition rate, mass loss rate, thermal load of the grate). Wood wastes of various grain size were subject of tests. Obtained results for pure wood and paper have also been presented for comparison. Experimental tests were carried out on laboratory scale. The advantage of such tests is large saving of costs which would have to be incurred for tests performed on a real object. Received values of the quantitative indexes may be used by shifting them from the devices in laboratory scale into industrial devices. They help in selecting technical parameters for the systems. Furthermore, they help to avoid errors of input data at the stage of realization of the new or modernized project of the incineration plant. The results show that the tested wood waste were similar regarding their physicochemical properties. The differences can be observed in heating values (14.30-19.91 MJ∙kg-1). The rate of ignition for all investigated materials is high (0.021-0.063 kg∙(m-2s-1)). Values of SZ and SUM are similar which suggests that the probability of unburned fraction of waste remaining at the end of grate of TPOK installation is low. The ratio SZ/SUM is between 0.79 and 1.49, higher than 1.0, which means that SZ > SUM. It seems to be right as the rate of mass decrement is lower than the rate of ignition.

WOOD RESEARCH Volume 64, Number 4, 2019
Małgorzata Kajda-Szcześniak and Tomasz J. Jaworski

Analysis of the formation and primary minimization of nitrogen oxides during the combustion of nitrogen-rich post-consumer wood waste

The article presents research on mechanism of formation of nitric oxide during combustion of wood derivative wastes in grid furnace boilers including waste incineration plants. Considering their elemental composition (large amount of nitrogen) they require supervision in thermal processes for their treatment. Concentrations of the formed nitric oxides, depending on the parameters of the combustion process and the size of the combusted grains, were subject to evaluation. The source of nitrogen in tested wastes is urea-formaldehyde resin used as a joint. The tests proved that the dominant mechanism is fueling mechanism for formation of nitrogen oxides. It is possible to limit this mechanism with original methods that interfere directly into the combustion process in the chamber (following temperature regime, granulation and humidity of the waste, intensity of mixing waste on the grill, stream of original air in the amount adjusted to the combustion phase in the grill). The article specifies main recommendations for the conduction of thermal transformation of wastes minimizing fuel nitric oxides.