To solve the problems of high investment and operation cost of the existing zero discharge process of desulphurization wastewater and difficult disposal of crystalline solid salt

this paper proposes a zero discharge system of "pretreatment-membrane concentration-bypass flue gas evaporation". The system's engineering design and construction has been completed in a coal-fired power plant in Shandong Province

and the commissioning operation and performance test has been carried out. The results show that

pretreatment method of "integrated softening clarification-mechanical filtration-ultrafiltration" ensures the normal operation of reverse osmosis

the integrated softening clarifier effluent content of Ca~(2+) is below 50 mg/L

that of Mg~(2+) is below 100 mg/L

the turbidity of filter effluent is about 0.2～0.4 NTU

and the average turbidity of ultrafiltration effluent is 0.05 NTU. Under the condition of 40% recovery rate

the desalination rate is about 99%

the operation pressure and pressure difference has no significant increase

and the conductivity of the water is about 0.40～0.55 mS/cm. The rotary atomization technology and two-phase flow technology total average spray water volume is 4.0 m~3/h

the flue gas circulation is normal

and the desulfurization wastewater droplets are stable fully evaporated

and the equipment is highly automated. This treatment system can achieve zero discharge of desulfurization wastewater of 350 MW coal-fired power plant

which has a good application prospect.