PROCESS FOR REMOVING ACID GAS FROM FLUE GAS BY USING WASTE HEAT OF SAME

摘要

A process for removing an acid gas from a flue gas by using waste heat of same. A flue gas is guided into a heat exchanger I, and the temperature of the flue gas is reduced. The flue gas enters a desulphurization absorption tower. Water in the pipe range of the heat exchanger is heated and vaporized to enter a phase splitter. The heat exchanger and the phase splitter are combined into a waste heat boiler. The generated vapor pressure is 3 to 6 atm. The water vapor is divided into three streams to enter a low-pressure steam turbine I, a low-pressure steam turbine II, and heater respectively. The water vapor drives the low-pressure steam turbine I to serve as the power source for a cooling machine, and cooled water is obtained. The cooled water serves as the refrigerant for the desulphurization absorption tower, a denitrification absorption tower, and a CO2 absorption tower respectively, so that the temperature thereof is respectively kept at a respective desired temperature. The second stream of water vapor is used for driving the low-pressure steam turbine II to compress the desulfutrated flue gas, and enters the denitrification absorption tower to remove the NOx, and at the same time produce a dilute nitric acid. The third stream of water vapor provides the heat source for a CO2 recovery tower through the heater H1, so as to recycle the CO2 absorbent for cycled use, and at the same time CO2 is generated and collected.