Experimental study on enhanced separation of a novel de-foulant hydrocyclone with a reflux ejector

The novel de-foulant hydrocyclone (DFH) with reflux device can effectively remove foulant from sewage and prevent the heat exchanger of the sewage source heat pump from clogging. However, the geometry of the reflux device has not been investigated in detail. The underflow pipe of the reflux device may interfere with the decontamination performance. In this study, the reflux device was converted into a reflux ejector, which caused a sucking effect on the underflow of the DFH. For further study, the effects of the suction angle, shape of the suction pipe, and motive flow rate on the separation performance were investigated. The ratio of the underflow rate to the overflow rate was used as the eject coefficient of the reflux ejector. Results showed that the suction effect was the best at suction angle of 30°; separation efficiency increased by 10% and the increase in energy consumption was less than 15 kPa compared with a suction angle of 90°. Simultaneously, the suction effect, separation efficiency, and energy consumption increased with the increase of the motive flow rate, and the maximum energy consumption does not exceed 25 kPa. This means that changing the reflux ejector geometry can optimize the decontamination performance.