| 摘要 |
The present invention relates to a selective catalytic reduction (SCR) denitrification system for the denitrification of exhaust gas, wherein some of the exhaust gas, of which the temperature is high at the front end of a heat exchanger, does not pass through the heat exchanger but bypasses through a temperature compensating bypass pipe so as to be injected into an exhaust pipe at the rear end of the heat exchanger such that the temperature of the exhaust gas which is introduced into a mixing chamber and a reactor can be maintained at an appropriate temperature for denitrification reaction, in the case where the temperature of the exhaust gas is lowered to be an inappropriate temperature for the denitrification reaction by the heat exchanger which recovers the waste heat of the exhaust gas at the front end of the reactor in a denitrification system which removes the nitrogen oxides of the exhaust gas discharged from an engine. In particular, a temperature sensor is mounted on the exhaust pipe at the rear end of the heat exchanger, and a flow control valve is provided to the temperature compensating bypass pipe line so as to be opened or closed under the control of a control unit and to control the flow rate of the exhaust gas which flows through the temperature compensating bypass pipe. Therefore, the control unit controls the flow control valve according to the temperature measured by the temperature sensor such that the flow rate of the exhaust gas which flows through the temperature compensating bypass pipe can be controlled according to the changes in the temperatures of the exhaust gas which is introduced into the mixing chamber or the reactor at the rear end of the heat exchanger. |
