Different kinds of main technologies for reducing the heat loss of flue gas exhausted from coal-fired boilers and the features of them have been briefly presented

and based on this

an approach to their matching behavior

with operating conditions of boilers as well as the basic principle for selecting technical kinds being emphatically made.The main conclusions are listed as in the following:(1) The non-balancing control technique of inlet flue gas flow rate into the air preheater

as well as the rotation-inversing measure for rotor in the air preheater should be popularized on large-capacity boilers as a common technology;(2) in creasing the surface area of air preheater should be considered as a firstly selecting technology for reducing heat loss of flue gas exhausted from the boilers

and the next is increasing the surface area of economizer;(3) under specific conditions

the low-pressure economizer technology can play a role in energy-saving

in the event of increasing surface area of the econoizer being feasible

a techno-economic comparison between them has to be carried out;(4) the heater technology of hot primary air is only suitable to the coal-pulverizing sytsem with large amount of cold air to bemixed.