| 摘要 |
<p>PURPOSE:To reduce the amount of flocculant while reducing the amount of formed sludge, by absorbing mercury in exhaust gas by a washing solution containing a liquid chelate and a metal salt and applying flocculative precipitation treatment to the used washing solution to immobilize and insolubilize mercury in formed sludge. CONSTITUTION:The exhaust gas 1a of an urban garbage incinerator is introduced into cooling and washing equipment 4 through a dust collector 2 to remove HCl and SOx therein while the washed exhaust gas is sent to a mercury washing tower 7 where contacted with a washing solution, which contains a liquid chelate comprising a water- soluble liquid polymer having a functional group rich in the reactivity with mercury such as an amino group and a metal salt such as CuCl or MnCl2, to absorb and remove mercury in the exhaust gas 1c. Because mercury forms a insoluble salt having a good sedimentation property through a chelate bond, a flocculant such as FeCl3 is added to the waste washing solution 10a in flocculative sedimentation installation 8 to treat the same and mercury is immobilized and insolubilized in the formed sludge. The waste solution 10b obtained by the solid-liquid separation in the flocculative sedimentation instrallation 8 contains only mercury equal to or less than an exhaust standard and high degree treatment of the waste solution becomes unnecessary or load is reduced.</p> |
