污泥添加量和添加磷酸对棉秆基成型燃料理化特性的影响OA

In the paper,cotton stalks were used as the raw material with sewage sludge and H3PO4 serving as additives.Formed particles were prepared via pelletization and subsequently carbonized under 500℃to produce formed charcoal.The effects of the sewage sludge addition and H3PO4 impregnation on the physicochemical properties of the formed fuel were mainly analyzed.Furthermore,the influence of carbonization and H3PO4 impregnation in improving the heavy metal stability within the formed charcoal were evaluated.The results show that as the amount of added sewage sludge increased,the apparent density of both the formed particles and the formed charcoal increased.The compressive strength of the formed particles showed a trend of first increasing and then decreasing,reaching a peak(32.76 MPa)when the mass ratio of sludge to cotton stalk was 1∶3,whereas the compressive strength of the formed charcoal continuously decreased.With the addition of H3PO4,both the apparent density and compressive strength of formed particles and formed charcoal improved.Compared to the samples without sludge and H3PO4,the addition of sludge reduced the calorific value and comprehensive combustion characteristic index of the formed charcoal by 13.01%～44.91%and 3.02%～13.31%,respectively.Compared to the formed particles,When the mass ratio of sludge to cotton stalk was 1∶3,the calorific value of the formed charcoal was 27.46 MJ/kg,and the potential ecological risk of Pb and Cd in the formed charcoal were reduced by 24.62%and 15.52%,respectively.Compared to the formed particles with H3PO4 impregnation,the potential ecological risk indexes of Pb and Cd in the formed charcoal with H3PO4 impregnation decreased by 18.22%and 8.86%,respectively.