Experimental investigation of fuel conversion characteristics during co-combustion of solid recovered fuel and coal in a 1 MWth circulating fluidized bed reactor

• Co-Combustion tests of SRF and coal were performed in 1 MW th CFB pilot plant. • Evaluated combustion traits with varying fuel compositions, focusing on thermodynamic and hydrodynamic stability. • In-bed gas measurements were conducted at three different fuel compositions. • Increasing SRF shares lowered the differential pressure and shifted the combustion to higher regions in the reactor. • Potential strategies to mitigate the effects of higher SRF shares are proposed. This study presents experimental results on co-combustion of hard coal and solid recovered fuel (SRF) conducted in a circulating fluidized bed (CFB) reactor with an internal diameter of 0.59 m, a height of 8.6 m, and a thermal load of 1 MW th . The high flexibility of the test facility enables testing of a variety of input materials under changing test conditions. The combustion of various fuel mixes ranging from 100 % hard coal to 100 % waste was tested to assess the impact of varying fuel ratios on the overall combustion process. As the proportion of SRF increased, a reduction in reactor differential pressure and particle density was observed. Moreover, combustion shifts to higher parts in the reactor when the share of SRF is increased. To further investigate the combustion conditions inside the reactor, three in-bed gas measurements were conducted, capturing the horizontal gas profiles of CO 2 , O 2 , and CO. An increase in SRF content led to elevated CO and O 2 levels, alongside a reduction in CO 2 , indicating an upward shift in the combustion zone. The behavior is attributed to the higher volatile content of SRF, which is in this experiment roughly 2.5 times the share of volatiles in hard coal and the lower bulk density of SRF. The study concludes by proposing potential strategies for reducing the impact of high SRF content on combustion conditions.