Abstract: In the desulphurization system of coalfired power plant, the faults of the gasgasheater (GGH) are occurred frequently, such as the equipment corrosion, dust deposition, scaling and blockage; and the high consumption of electricity, steam and water; so it is the biggest factor influencing on the system operating rate. In recent years, in the new built power plants, the GGH was eliminated and replaced by wet chimney; but this causes some new problems, such as the pollution in the vicinity, the dropping of the anticorrosive materials of the chimney, the higher water consumption and so on. In order to better develop the functions of GGH, a reformation scheme of new type phasetransition heat exchanger was put forward, which provides a solving way for higheffective, lowconsumption and safe operation of desulphurization system. 

Key words: gas-gas-heater (GGH), phase-transition heat exchanger, liquid-phase forced circulating heat exchanger, high voltage electrostatic demister