A flue gas treatment process which can realize simultaneous condensation and removal of CO_2 and SO_2 through flue gas scrubbing by low temperature pentane liquid is developed. In this process

two spraying towers are used to cool the flue gas. In the first spraying tower

the flue gas is cooled closed to freezing point of water by cold water scrubbing. In the second spraying tower

the flue gas is further cooled to the desublimation temperatures of SO_2 and CO_2 by low temperature n-pentane liquid spraying

the SO_2

CO_2 and H_2O components obtained from washing condensation are insoluble in n-pentane

so they can be separated from the washing solution. By using the Aspen Plus software

this paper establishes the desulfurization and decarbonization process model of 600 MW coalfired units by low temperature condensation method. Through material and energy balance calculation

the SO_2 and CO_2 removal efficiency as well as the system energy consumption are analyzed. The results show that

when the flue gas temperature is decreased to –116 ℃

the capture rate of CO_2 can reach 90% and that of SO_2 can approach to near 100%. The energy consumption of the system is about 80.25 MW(188.6 kW·h/t CO_2) when the captured CO_2 is in gaseous form

and it is about 114.56 MW(269.2 kW·h/t CO_2) when the captured CO_2 is in liquid form. The energy consumption is about 30% lower than that of the conventional amine-based CO_2 capture technology.