5.5　Sintering Exhausting and Flue Gas Cleaning

5.5.1　The average air volume per suction area of sinter machine for sizing main exhaust fan should be 90±5m3/（min·m2）（Actual condition）.When limonite and siderite are adopted as the major raw materials，the air rate can be more than 95m3/（min·m2）（Actual condition）.

5.5.2　The exhaust fan pressure shall be determined according to raw material properties，bed depth，pressure drop at grate bars，pipeline and deust collectors as well as site mean sea level etc..The gauge pressure at fan inlet should be-16kPa--18kPa for large-scale and medium-scale sinter machines.

5.5.3　Two-stage sintering flue gas dedusting shall be adopted，collecting main is used at the first stage，dust collector is used at the second stage.Double-collecting main shall be adopted for the large-scale sinter machines.

5.5.4　When electrostatic precipitators are adopted for dedusting of process gases for large sized and medium sized sinter machines，the collecting main shall be equipped with the automatic flue gas temperature adjustment device.

5.5.5　The double-lip dust valve should be used for dust dumping device at the collecting main.

5.5.6　The height of the process stack shall be calculated and final determined in combination with actual conditions.

5.5.7　The main exhaust fan in plateau area shall be selected according to the local atmospheric pressure and oxygen content of atmosphere，and the motor power shall be determined according to the local motor efficiency.

5.5.8　When the flue gas recirculation process is adopted，it shall be determined according to the oxygen content and pressure of recirculating flue gas.

5.5.9　The hot sintering flue gas should be utilized，and its utilization rate shall be determined according to the sintering flue gas dew point temperature.

5.5.10　The newly built sinter machine shall be synchronously installed with process gas cleaning facilities for jointly removal pollutants in the flue gases，such as SO2，NOX，dust，fluoride，heavy metal and dioxin，etc..The flue gas cleaning system shall be operated stably，its by-product shall be reasonably utilized without any secondary pollution.

5.5.11　The comprehensive flue gas control shall meet the requirements of prevailing national standard"Emission standard of air pollutants for sintering and pelletizing of iron and steel industry"GB 28662.

5.5.12　When the electrostatic precipitators are adopted for dedusting process gases for large and medium sized sinter machines，the dust from the third and the fourth electrical fields shall be treated according to the characteristics of dust which may impact on product quality.In this case，this dust can be disposed properly.