For the circulating fluidized bed(CFB) unit adopting the low-temperature economizer and the rolling slag cooler to recover the low-temperature waste heat

there is a problem of insufficient condensate flow distribution. To solve this problem

a new energy-saving method of a collaborative waste heat utilization system consisting of the slag cooler

air heater and low temperature economizer is proposed in this study. In this system

the slag cooler and air heater are closed cycles. The slag cooler recovers some of the residual heat from the bottom slag of the boiler

which is used to heat the first and second air of the air preheater inlet. And the increased waste heat of exhaust air flue gas at the outlet of the air preheater is recovered by the low-temperature economizer.Taking a supercritical 350 MW CFB unit in Shanxi province as an example

the economics of both the collaborative waste heat utilization system and the conventional rolling slag cooler and low temperature economizer system are compared and analyzed. The results show that

the coal consumption of the collaborative waste heat utilization system can be reduced by 0.83 g/(k W·h) compared with the conventional system

and this system has certain popularization significance in energy conservation and consumption reduction of the CFB unit.