The purpose of this thesis is to find the optimum point of boiler heat recovery system which using direct contact method.
For this, the cost of initial investment and operating, and the savings are calculated for different 36(3x3x4) system conditions.
The condition is selected as that $T_1$(outlet gas temperature of air preheater) is 80, 100, 120 ℃, $T_8$(outlet air temperature of air direct contact tower) is 30, 35, 40, 45 ℃, and $T_5$ (inlet water temperature of air direct contact tower) is $T_5=T_8+1$, $T_8+3$, $T_8+5 ℃.
The condition $T_1=80 ℃$, $T_8=45 ℃$, $T_5=T_8+3 ℃$ is found as a optimum point of boiler heat recovery system which using direct contact method, which means bigger heat recovery makes bigger savings.
