Abstract

t Organic waste has been playing an increasingly important role in the energy market as those that may support the economies in pursuing towards decarbonization by increasing the share of renewables in the overall energy balance. In this group of alternative fuels, meat-and-bone meals being a post-production waste of the steadily developing meat industry, constitute a considerable proportion. Though they are rich in minerals, their direct use as natural fertilizer has been restricted to eliminate the spread of potential pathogens. This has focused the worldwide interest on thermal utilization of this type of fuel. Still, there are relatively few units dedicated to deal with large streams of meals. To provide their safe destruction, the conversion process must ensure specific conditions regarding the temperature and residence time. Therefore, most technologies developed to date involve the fluidized bed combustion. By virtue of nature and the variety of physicochemical properties of animal meals, the in-depth analyses of a raw material and its thermal behaviour need to be carried out on the way to develop the efficient and low-emission conversion technology. The concept of the said staged combustion of animal meal has therefore been supported by extensive studies, including the investigation of specific issues related to the process stages, such as drying, devolatilization, gas and char combustion. The developed technology appears to respond to the challenges encountered in the conversion of waste organics, providing the possibility to utilize fuels with a moisture content of up to 90%wt, while keeping the acceptable emission levels (NOx, CO, SO2 and HCl). The 12 MW operating pilot-scale plant tested while supplied with meat-and-bone meal has exhibited high efficiency, 88.4–84.8% depending on a facility load, offering a complete fuel combustion resulting in a flue gas being free from flammable gas compounds, and the ashes with low percentages of combustibles.

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Authors (5)