Energy conservation boiler plant

To illustrate, in a fossil fuel power plant the loss of boiler air preheater(s) can create a sudden increase in flue gas temperature from <300°F up to 500°-700°F for a brief (e.g., 20-30 minute) period. (Air preheaters are energy conserving heat exchangers that heat incoming boiler combustion air with hot boiler flue gas which is thereby cooled prior to particulate scrubbing. If an air preheater fails, the hot flue gas will not be cooled by the heat transfer to the in-... 

How can the low second law efficiency of the boiler in Example 5.7 and the low first and second law efficiencies of the power plant of Example 5.8 be improved How, in other words, can we improve the utilization of the fuel heating value, thus effecting energy conservation ... 

---