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Show the activated coke moving bed test were respectively 1500-2700 NmJ/H, and the temperature of the flue gas at the moving bed inlet was 120-145 degC. The activated coke after adsorption of PCDDs/PCDFs and Hg was mechanically discharged from the bottom. For the concentrations of PCDDs/PCDFs and Hg in the flue gas,the flue gas at the inlet/outlet of dust collector and the flue gas at the inlet/outlet of activated coke moving bed were simultaryeously sampled, and the samplings were analyzed according to the JIS method, and the reduction ratios were calculated. 3. Test results 3.1 Injecting activated carbon powder into flue gas 1) PCDDs/PCDFs The result of this test is shown in Fig.2. While the destruction ratio of PCDDs/PCDFs by the ordinary practice of injecting slaked lime only is 23.6%, the destruction ratio where activated carbon is injected is higher than 80%, showing that injection of activated carbon increases the destruction ratio due to its adsorbing function. Incidentally, the concentration of PCDDs/PCDFs in the flue gas at the bag filter outlet is 0.16-0.66 ng/NmJ (TEQ-International). This suggests the possibility of achieving 0.5 ng/NmJ , (TEQ-International) shown in the said guideline with this process. 2) Hg The result of this tes~ is shown in Fig.3. As is evident from this figure, while the destruction ratio of Hg emission where no activated carbon was injected was 56%, the destruction ratio of Hg where activated carbon was injected was higher than 95%, and the Hg concentration in the flue gas at the bag filter outlet was lower than 0.01 mg/NmJ . 3.2 Passing flue gas into activated coke moving bed 1) PCDDs/PCDFs The test result is shown in Fig.4. As is evident from this figure, the destruction ratio of PCDDs/PCDFs increases with layer depth. In the case of layer depth 1500 mm, the destruction ratio is 91-93%,and PCDDs/PCDFs concentration in the exhaust gas at outlet is 0.02-0.03ng/NmJ (TEQInternational). which is enough lower than 0.5mg/NmJ shown in the guideline. 2) Hg The test result is shown in Fig.5. The concentration of Hg at the system inlet was as low as 0.02-0.14 mg/Nm3 ,because the gas had passed the bag fi1ter,but the concentration of Hg at the outlet was less than 0.03mg/NmJ and Hg destruction ratio was 76-100%. It had been anticipated that the higher was the layer of activated coke,the higher would be the Hg destruction ratio. Contrary to our anticipation,however,the Hg destruction ratio with the 1000 mm high layer was lower than that with the 500 mm high layer,This may be due to the analytical error attributable to the low Hg concentration at the inlet and the outlet Hg concentration close to the detection limit. 4. Conclusion As a result of conduction the present test aiming at removal of Hg and PCDDs/PCDFs contained in flue gas.It has became known that adoption of either of the process of injecting activated coal powder into exhaust gas flue and the process of adsorption by means of activated coke moving bed can reduce Hg concentration and PCDDs/PCDFs concentration in flue gas. We will continuously make developmental study aiming at practical application of these processes. REFERENCES (1) E. Shibuya and K. Yoshikubo; "Reduction of Hg in flue gas from Municipal Solid Waste Incinerator",The 13th National Convention of Municipalities on Cleaning"(1992) 129-131 (2) E. Shibuya ,T. sato and T. Nomura; "Reduction of Hg and PCDDs/PCDFs emission from MSW Incinerator, " '92 Symposium on Environmental Engineering, (1992) 171-173 |