Modification of lignite ash fusion temperatures by the addition of different types of sewage sludge

Analysis of sewage sludge ashes from air and oxy-fuel combustion in a circulating fluidized-bed

“…The most interesting is the phosphate of calcium and magnesium as a low-solubility mineral named whitlockite. The presence of whitlockite mineral in sewage sludge ashes was confirmed by [17,18]. Although the sewage sludge was oxy-combustion and the concentration of CO2 was higher than air combustion the carbonates are not detected.…”

“…Silica sand (particles smaller than 400 μm) to a mass of 0.3 kg constituted the inert bed. The gases that make up gas mixtures are supplied from cylinders (12) to a mixer (17) and then transferred via a preheater (8) directly into the combustion chamber. The flow rates of gases are controlled by valves (16) and measured by rotameters (15).…”

Effect of sludge addition to coal on Na, K and S volatilisation in ashing process and ash fusibility

“…Apart from the differences in rank and ash yield, the bituminous coal has much lower sulphur content but much higher Fe content than the lignite used in the previous work [25]. Moreover, volatilisation of Na, K and S has been studied more deeply.…”

“…Some works [16][17][18][19][20][21][22][23][24][25] have been published on slagging and AFTs for sewage sludge and coal-sludge blends. The addition of sewage sludge to coal has a significant effect on AFTs of coal.…”

“…Zhang et al [23] studied the influence of phosphorus on ash fusion temperatures of coal-sewage sludge blends, and they found that interactions of main minerals of sludge (CaO, P 2 O 5 and aluminosilicates) led to the formation of molten agglomerates, the phosphorus effect depending on the molar ratio Al 2 O 3 /(CaO + Na 2 O + K 2 O) of blend ashes. Also, in a previous work [25], the effect of sludge addition to a lignite with high sulphur content was studied. The addition of sludge to the lignite reduced AFTs.…”