In-situ measurement of alkali metal concentrations and temperatures during the incineration of municipal solid waste and sludge

Abstract

The release of alkali metals in municipal solid waste (MSW) incineration caused corrosion of thermal equipment and slagging in incinerator. By using a spectrometer and multispectral camera, the concentrations of Na and K, flame temperatures and emissivities in an industrial incinerator with different proportions of food waste, sludge, waste paper and waste fabric were measured in this study. The flame temperatures on the left wall decreased from 1479.5 K to 1366.2 K as the height increased from 13.4 m to 16.9 m. Flame temperatures near the left side of the incinerator were 8.9 % higher than those near the right side, which were caused by the ununiform distribution of MSW. The concentrations of Na and K increased by 67.16 % and 86.9 % with the primary air flow increased by 3969.35 t/h. The average concentrations of Na and K at 16.9 m of the left wall decreased by 25.87 % and 37.53 % with the decreasing of food waste and increasing of sludge. The Na and K contents in fixed carbon were greater than those in volatile matter and ash in fuels. Compared with waste paper and waste fabric, the blending of sludge with food waste was more effective on reducing the release of Na and K. When the proportion of food waste: sludge was set as 8:2, the lowest releases of Na 20.75 ppm and K 5.30 ppm existed in the incineration of food waste and sludge. The concentrations of Na and K decreased by 17.3 % and 46.9 % with the increasing of waste paper, the waste paper was a better alternative to sludge when mixed with MSW.