Clean flue gas recycling technology

The FGD unit adopts the unique clean flue gas recycling technology of Lonjing. The recirculating duct connects the outlet duct of ID fan and the inlet duct of reactor, and the recirculating flue gas can be controlled flexibly according to the boiler load through the damper.Because of the performance of clean flue gas recirculation, the desulfurization reaction can be effectively guaranteed not to be affected by the boiler load change, thus making the FGD system work reliably and efficiently, and ensuring the downstream ESP work stably. 

By use of the static pressure drop between the outlet of ID fan and the inlet of reactor, there is no need to install a separate exhaust fan. According to the load change, adjusting the damper of the recirculating duct to control the flow of purified flue gas into the inlet of reactor, so that the velocity of the venturi nozzle in the reactor is kept relatively stable.In general, when the boiler load is reduced to 70%, the damper is opened to make the inlet flue gas volume of the reactor reach 80% of the designed load, while the load returns to 80%, damper is closed. The installation and utilization of clean flue gas recirculation duct not only can ensure the stability of desulfurization process but also make the ID fan operate under rated conditions, which is beneficial to the service life of it. The designed flow rate of the clean flue gas recirculation duct is 40% of the designed inlet flue gas volume of the FGD system. The designed flow rate of the flue gas is 23.8m/s.he size of the clean flue gas recirculation duct is 3000mm×3000mm, an internal support rod is set in it, and the damper of the clean flue gas recirculation duct should be installed in the duct near the outlet of ESP1.