Method and apparatus for prolonging continuous operation period of methanol-to-olefins water washing process

A method for prolonging a continuous operation period of a methanol-to-olefins washing water treatment process, comprising the following steps:

• (i) subjecting methanol-to-olefins washing water to micro-cyclone treatment to remove free oil from the water;
• (ii) sending the washing water deoiled by microcyclone to a fluidized bed separator for treatment to remove emulsified oil, dispersed oil and fine catalyst powder from the water, wherein the fluidized bed separator runs continuously until an accumulated operating pressure difference reaches 0.05-0.3 MPa, and then the washing water is fed for backwashing, optionally nitrogen gas is further added to mix with the washing water for backwashing, so as to fully fluidize a granular bed of the fluidized bed separator to a boiling state;
• (iii) adjusting a backwash flow rate to 50-90 m3/h to release intercepted catalyst powder and clear dirt contained in voids;
• (iv) subjecting a gas-liquid-solid mixture generated by the backwashing to three-phase separation, wherein a resulting filter material is returned to the granular bed, and a backwash liquid entraining the catalyst and a backwash gas are discharged separately;
• and
• (v) switching the fluidized bed separator to a normal working state after the backwashing is finished, so that activity regeneration of the granular bed is accomplished, and operation continues.